水利专业混凝土重力坝毕业论文中英文资料外文翻译文献

Concrete Gravity DamThe type of dam selected for a site depends principally on topographic, geologic,hydrologic, and climatic conditions. Where more than one type can be built, alternative economic estimates are prepared and selection is based on economica considerations.Safety and performance are primary requirements, but construction time and materials often affect economic comparisons.Dam ClassificationDams are classified according to construction materials such as concrete or earth. Concrete dams are further classified as gravity, arch, buttress, or a combination of these. Earthfill dams are gravity dams built of either earth or rock materials, with particular provisions for spillways and seepage control.A concrete gravity dam depends on its own weight for structural stability. The dam may be straight or slightly curved, with the water load transmitted through the dam to the foundation material. Ordinarily, gravity dams have a base width of 0.7 to 0.9 the height of the dam. Solid rock provides the best foundation condition. However, many small concrete dams are built on previous or soft foundations and perform satisfactorily. A concrete gravity dam is well suited for use with an overflow spillway crest. Because of this advantage, it is often combined with an earthfill dam in wide flood plain sites.Arch dams are well suited to narrow V- or U-shaped canyons. Canyon walls must be of rock suitable for carrying the transmitted water load to the sides of the canyon by arch action. Arch sections carry the greatest part of the load; vertical elements carry sufficient load through cantilever action to produce cantilever deflections equal to arch deflections. Ordinarily, the crest length-to-height ratio should be less than 5, although greater ratios have been used. Generally, the base width of modern arch dams is 0.1 to 0.3 the height of the impounded water. A spillway may be designed into the crest of an arch dam.Multiple arches similarly transmit loads to the abutment or ends of the arch. This type of dam is suited to wider valleys. The main thrust and radial shears are transmitted to massive buttresses and then into the foundation material.Buttress dams include flat-slab, multiple-arch, roundhead-buttress, and multiple-dome types. The buttress dam adapts to all site locations. Downstream face slabs and aprons are used for overflow spillways similar to gravity dam spillways. Inclined sliding gates or light-weight low-head gates control the flow.The water loads are transmitted to the foundation by two systems of load-carrying members. The flat slabs, arches, or domes support the direct water load. The face slabs are supported by vertical buttresses. In most flat-slab buttress dams, steel reinforcement is used to carry thetension forces developed in the face slabs and buttress supports. Massive-head buttresses eliminate most tension forces and steel is not necessary.Combiantion designs may utilize one or more of the previously mentioned types of dams. For example, studies may indicate that an earthfill dam with a center concrete gravity overflow spillway section is the most economial in a wide, flat valley. Other design conditions may dictate a multiple-arch and buttress dam section or a buttress and gravity dam combination.Site ExplorationThe dam location is determined by the project’s functions. The exact site within the general location must be determined by careful project consideration and systematic studies.In preliminary studies, two primary factors must be determined-the topography at the site and characteristics of the foundation materials. The first choice of the type of dam is based primarily on these two factors. However, the final choice will usually be controlled by construction cost if other site factors are also considered.Asite exploration requires the preparation of an accurate topographic map for each possible site in the general location. The scale of the maps should be large enough for layout. Exploration primarily determines the conditions that make sites usable or unusable.From the site explorations, tentative sketches can be made of the dam location and project features such as power plants. Physical features at the site must be ascertained in order to make a sketch of the dam and determine the position of materials and work plant during construction. Other factors that may affect dam selection are roadways,fishways, locks, and log passages.TopographyTopography often determines the type of dam. For example, a narrow V-shaped channel may dictate an arch dam. The topography indicates surface characteristics of the valley and the relation of the contours to the various requirements of the structure. Soundness of the rock surface must be included in the topographic study.In a location study, one should select the best position for the dam. An accurate sketch of the dam and how it fits into the topographic features of the valley are often sufficient to permit initial cost estimates. The tentative location of the other dam features should be included in this sketch since items such as spillways can influence the type and location of the dam.Topographic maps can be made from aerial surveys and subsequent contour plotting or they can be obtained from governmental agencies. The topographic survey should be correlated with the site exploration to ensure accuracy. Topographic maps give only the surface profile at thesite. Further geological and foundation analyses are necessary for a final determination of dam feasibility.Foundation and Geological InvestigationFoundation and geological conditions determine the factors that support the weight of the dam. The foundation materials limit the type of dam to a great extent, although such limitations can be compensated for in design.Initial exploration may consist of a few core holes drilled along the tentatively selected site location. Their analysis in relation to the general geology of the area often rules out certain sites as unfeasible, particularly as dam height increases. Once the number of possible site locations has been narrowed down, more detailed geological investiagtions should be considered.The location of all faults, contacts, zones of permeability, fissures, and other underground conditions must be accurately defined. The probable required excavation depth at all points should be derived from the core drill analysis. Extensive drilling into rock formations isn’t necessary for small dams. However, as dam height and safety requirements increase, investigations should be increased in depth and number. If foundation materials are soft, extensive investigations should determine their depth,permeability, and bearing capacity. It is not always necessary orpossible to put a concrete dam on solid rock.The different foundations commonly encountered for dam construction are: (1)solid rock foundations, (2) gravel foundations, (3) silt or fine sand foundations, (4) clay foundations, and (5) nonuniform foundation materials. Small dams on soft foundation ( item 2 through item 5 ) present some additonal design problems such as settlement, prevention of piping, excessive percolation, and protection of foundation from downstream toe erosion. These conditions are above the normal design forces of a concrete dam on a rock foundation. The same problems also exist for earth dams.Geological formations can often be pictured in cross-section by a qualified geologist if he has certain core drill holes upon which to base his overall concept of the geology. However, the plans and specifications should not contain this overall geological concept. Only the logs of the core drill holes should be included for the contractor’s estimates. However, the geological picture of the underlying formations is a great aid in evaluating the dam safety. The appendix consists of excerpts from a geologic report for the site used in the design examples.HydrologyHydrology studies are necessary to estimate diversion requirements during construction, to establish frequency of use of emergency spillways in conjunction with outlets or spillways, to determine peak dischargeestimates for diversion dams, and to provide the basis for power generation. Hydrologic studies are complex; however, simplified procedures may be used for small dams if certain conservative estimates are made to ensure structural safety.Formulas are only a guide to preliminary plans and design computations. The empirical equations provide only peak discharge estimates. However, the designer is more interested in the runoff volume associated with discharge and the time distribution of the flow. With these data, the designer knows both the peak discharge and the total inflow into the reservoir area. This provides a basis for making reliable diversion estimates for irrigation projects, water supply, or power generation.A reliable study of hydrology enables the designer to select the proper spillway capacity to ensure safety. The importance of a safe spillway cannot be overemphasized. Insufficient spillways have caused failures of dams. Adequate spillway capacity is of paramount importance for earthfill and rockfill dams. Concrete dams may be able to withstand moderate overtopping.Spillways release excess water that cannot be retained in the storage space of the reservoir. In the preliminary site exploration, the designer must consider spillway size and location. Site conditions greatly influence the selection of location, type, and components of a spillway. The design flows that the spillway must carry without endangering the dam areequally important. Therefore, study of streamflow is just as critical as the foundation and geological studies of the site.附录2外文翻译混凝土重力坝一个坝址的坝型选择，主要取决于地形、地质、水文和气候条件。

水利工程三峡水利枢纽工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)The Three Gorges ProjectsFirst. The dam site and basic pivot disposalThe Three Gorges Projects is select to be fixed on San Dou Ping in Yichang, located in about 40 kilometers of the upper reaches of key water control project of Ge Zhou Ba which was built. River valley, district of dam site, is widen, slope, the two sidesof the bank is relatively gentlely. In the central plains have one island (island, fort of China,), possess the good phased construction water conservancy diversion condition. The foundation of pivot building is the hard and intact body of granite. Have built Yichang and gone to stride bridge that place of 4 kilometers in the about 28 -km-long special-purpose expressway of building site and dam low reaches --West Yangtze Bridge of imperial tomb. Have also built the quay of district of a batch of dams. The dam district possesses the good traffic condition.Two. Important water conservancy project buildings1. damThe dam is a concrete gravity dam, which is 2309 meters long, it’s height is 185meters , the dam is 181 meters high the most. Release floodwater dam section lie riverbed, 483 of the total length, consist of 22 form hole and 23 release floodwater in the deep hole, among them deep hole is imported 90 meters , the mouth size of hole is 7*9 meters; Form hole mouth is 8 meter wide, overflow weir is 158 meters, form hole and deep hole adopt nose bank choose, flow way go on and can disappear. Dam section lies in and releases floodwater on a section of both sides of the dam in the hydropower station, there are hydropower stations that enter water mouth. Enter water mouth baseplate height 108 meters. Pressure input water pipeline for carry person who in charge of, interior diameter 12.40, adopt the armored concrete to receive the strength structure. Make and let out flow of 102500 cubic meters per second the most largely in the dam site while checking the flood.2. power stationsThe power stations adopt the type after the dam to assign the scheme, consist of two groups of factory buildings on left, right and underground factory building altogether. Install 32 sets of hydroelectric generating set together, 14 factory buildings of left bank among them, 12 factory buildings of right bank, 6 underground factory buildings. The hydraulic turbine, in order to mix the flowing type, the specified capacity of the unit of the unit is 700,000 kilowatts.3. open up to navigation buildingThe open up to navigation buildings include permanent lock and ship lift (of the the technological public relations, the steel cable that plans to be replaced with spiral pole technology in the original plan promotes technology), lie in the left bank. Permanent lock double-line five continuous chain of locks. Single grades of floodgate room effective size for 280*34*5, can pass the 10,000 ton-class fleet. The promoting type for single track first grade vertically of the ship lift is designed, it is 120*18*3.5 meters to bear the effective size of design of railway carriage or compartment of ship, can pass a combination vessel of 3000 tons once. Total weight is 11800 tons to bear the design of railway carriage or compartment of ship when operating, it is 6000 newtons to always promote strength.Three.The major project amount and arranges in time limit The subject building of the project and major project amount of the waterconservancy diversion project are: Excavate 102,830,000 cubic meters in cubic metre of earth and stone, fill out and build 31,980,000 cubic meters in cubic metre of earth and stone, concrete builds 27,940,000 cubic meters, 463,000 tons of reinforcing bars, make and fit 32 with hydroelectric generating set. All project construction tasks were divided into three stages and finished, all time limit was 17 years. The first stage (1993-1997 year) is preparation of construction and the first stage of the project, it takes 5 years to construct, regard realizing damming in the great river as the sign. The second stage (1998-2003 year) is the second stage, it takes 6 years to construct, lock as initial conservation storage of the reservoir, the first batch of aircrews generate electricity and is open up to navigation with the permanent lock as. The third stage (2004-2009 year) is the third stage of the project, it takes 6 years to construct, regard realizing the sign all aircrews generate electricity and finish building with all of multi-purpose project as. One, two project finish as scheduled already, the third stage of the project in inside the plan to construct too, ship lift tackle key problems of not going on intensely.Four. Enormous benefit of the Three Gorges Projects The Three Gorges Projects is the greatest water control project in China ,also in the world , it is the key project in controlling and developing the Changjiang River. The normal water storage level of the Three Gorges Projects reservoir is 175 meters, installed capacity is 39,300 million cubic meters; The total length of the reservoir is more than 600 kilometers, width is 1.1 kilometers on average; The area of the reservoir is 1084 sq. km.. It has enormous comprehensive benefits such as preventing flood, generating electricity, shipping,etc..1. prevent floodPrimary goal of building the Three Gorges Projects is to prevent flood . The key water control project in Sanxia is the key project that the midstream and downstream of the Changjiang River prevent flood in the system. Regulated and stored by the reservoir of Sanxia, form the capacity of reservoir in the upper reaches as river type reservoir of 39,300 million cubic meters, can regulate storage capacity and reach 22,150 million cubic meters, can intercept the flood came above of Yichang effectively, cut down flood crest flow greatly, make Jingjiang section prevent floodstandard meet, improve from at present a about over ten years to once-in-a-hundred-year. Meet millennium first special great flood that meet, can cooperate with Jingjiang flood diversion partition application of flood storage project, the crushing calamity of preventing the occurrence of both sides of section of Jingjiang and bursting in the main dike, lighten midstream and downstream losing and flood threat to Wuhan of big flood, and can create conditions for administration of Dongting Hu district.2. generates electricityThe most direct economic benefits of the Three Gorges Projects is to generate electricity . Equilibrate the contradiction that contemporary China develops economic and serious energy shortage at a high speed, the hydroelectric resources that a clean one can be regenerated are undoubtedly optimum choices. The total installed capacity of power station of Sanxia is 18,200,000 kilowatts, annual average generation is 84,680 million kilowatt hours. It will offer the reliable, cheap, clean regenerated energy for areas such as East China, Central China and South China of economic development, energy deficiency,etc.It play a great role in economic development and environmental pollution of reducing.Electric power resource that the Three Gorges Projects offers, if given a workforce of electricity generation by thermal power, mean building 10 more thermal power plants of 1,800,000 kilowatts, excavate more 50 million tons of raw coals every year on average. Besides environment of influencing of the waste residue, it will also discharge a large number of carbon dioxide which form the global greenhouse effects every year, cause the sulfur dioxide of acid rain, poisonous gas carbon monoxide and nitrogen oxide. At the same time, it will also produce a large amount of floating dust, dustfall,etc… Thermal power plant and abandon dreg field extensive occupation of land seize more land from East China, Central China area that have a large population and a few land just originally this. This not only makes China bear the pressure that greater environment brings in the future, cause unfavorable influence on the global environment too.3. shippingSanxia reservoir improve Yichang go to Chongqing channel of the ChangjiangRiver of 660 kilometers notably, the 10,000 ton-class fleet can go to the harbour of Chongqing directly. The channel can rise to 50 million tons from about 10 million tons at present through ability in one-way year, transporting the cost can be reduced by 35-37%. Unless until reservoir regulate, Yichang low water flows minimum seasons downstream,whose name is can since at present 3000 cubic meters /second improve until 5000 cubic meters per above second, the shipping condition get greater improvement too to enable the Changjiang River in low water season of midstream and downstream.Five. The questions in building the Three Gorges Projects1. silt issuethe Changjiang River Yichang Duan Nian amount of sand failed 530 million tons, silt the reservoir of Sanxia up. The reservoir blocks water level is 175 meters high, installed capacity is 39,300 million m3 normally,its die water level is 145 meters, the minimum capacity of a reservoir is 17,200 million m3, storage capacity 22,100 million m3, the conservation storage regulates the capacity of reservoir 16,500 million m3. The operation scheme of the reservoir is: Limit height is 145 meters of water level, in flood season, meet flood adjust big under 56700 m3 per second, and power station smooth to let out through deep hole over 3 years, can reduce the sand of the reservoir to deposit. Great flood comes, the reservoir is adjusted bigly, still put and let out 56700 m3per second; Deposit towards the reservoir after the flood. The reservoir begins conservation storage, between about two months and normal water storage level 175 meters high in September. The water level of the storehouse is dropped to 155 meters high before the flood next year, utilize conservation storage to generate electricity. In 155 meters water level, can keep the river shipping of Sichuan. By flood season, the water level was dropped to 145 meters water level again, because the flow was large at that time, could keep the river shipping of Sichuan. This is a reservoir operation scheme of innovation.2. question that the slope comes down by the bank of reservoir areaThe question that the slope comes down is through detailed geological survey by 2 reservoir area banks, there is several to come down potentially on water bank of Kuku of Sanxia, the big one can be up to millions of m3. But closest to dam sitepotential landslide, too far on 26 kilometers, such as happen, come down, shock wave that evoke get dam disappear, reduce 2-3 meters to to be high, it is safe not to influence the dam. In addition, if the slippery wave happens in the bank of the storehouse, because the reservoir is wide and deep, will not influence shipping.3. engineering question of the pivotThe pivot of Three Gorges is 185 meters high concrete gravity dam pivots and 18,200,000kW, the project amount is large, but all regular projects after all, our country has more experience. The stability problem of some foundation can meet the safe requirement through dealing with. 700,000kW hydroelectric generating set, imported from foreign countries in the first batch, was made by oneself at home later. The more complicated one is lock of five grades of Line two, deep-cut in the rock bank, slope reaches 170 meters at the supreme side, the underpart floodgate room vertical 60 meters, high rock slope stability worries about. But the meticulous research of engineer and constructors is designed, blown up and the anchor is firm and excavating, the rock slope is steady in a long-term. There is ship lift of 3000t passenger steamer, it is the biggest in the world, in course of designing and studying, and repair the test and use the ship lift first.4.ecological environment problemThe respect useful to ecological environment of the Three Gorges Projects is: Prevent and cure downstream land and cities and towns to flood, reduce the air pollution of electricity generation by thermal power, improve some climate, the reservoir can breed fish etc.. The respect disadvantageous to ecology is: Flood more than 300,000 mu of cultivated land, ground of fruit is more than 200,000 mu, immigrants reach the highland by the storehouse, will destroy the ecological environment, the still water weakens the sewage self-purification ability, worsen water quality, influence reproduction of the wild animal,etc. in the reservoir. So is both advantageous and disadvantageous, do not hinder building the Three Gorges Projects. Should reduce being unfavorable to minimum extent, it is mainly that reservoir immigrants want to plant trees and grass, build the terraced fields, ecological environment protection, does not require the self-sufficiency of grain. Accomplish these, want making a great effort and fund. Control blowdown such as Chongqing,Fuling, Wan County, carry on sewage disposal, protect the water quality of the reservoir, protect the wild animal, set up the protection zone. Although ecological environment protection is difficult, must solve and can solve. As for the scenery of Sanxia, because the high near kilometer of rock bank, and Sanxia dam is only in fact higher than the river surface 110 meters. The scenery basically remains unchanged, the high gorge produces Pinghu, increase even more beautifully.Six. Immigrant's question in the reservoir areaThe reservoir of Sanxia will flood 632 sq. km. of land area, will involve Chongqing, 20 county (market) of Hubei. The reservoir of Sanxia floods and involves 2 cities, 11 county towns, 116 market towns; Flood or flood 1599 of industrial and mining enterprises that influence, reservoir flood line there are 24,500 hectares of cultivated land in all; Flood 824.25 kilometers of highways, 92,200 kilowatts of power stations; The area of house of flooding area is 34,596,000 square meters, total population of living in the flooding area is 844,100 people (agricultural population 361,500 people among them). Consider population growth and other factors of moving etc. two times during construction, the total population of trends of reservoir immigration allocation of Sanxia will be up to 1,130,000 people. The task is arduous, but must find a room for good immigrants, make its life improve to some extent, help immigrants to create the working condition, live plainly and struggle hard through 20 years, grow rich. Most immigrants retreat to the highland, it is nonlocal that some immigrants get. The reservoir of Sanxia will flood 632 sq. km. of land area, will involve Chongqing, 20 county (market) of Hubei. The reservoir of Sanxia floods and involves 2 cities, 11 county towns, 116 market towns; Flood or flood 1599 of industrial and mining enterprises that influence, reservoir flood line own cultivated land (suck the ground of mandarin orange) 24,500 hectares in common; Flood 824.25 kilometers of highways, 92,200 kilowatts of power stations; The area of house of flooding area is 34,596,000 square meters, The total population of living in the flooding area is 844,100 people (agricultural population 361,500 people among them). Consider population growth and other factors of moving etc. two times during construction, the total population of trends of reservoir immigration allocation of Sanxia will be up to 1,130,000 people.1.exploration and opening of the immigrants in SanxiaThe exploration of an immigrant in Sanxia and open country are in the engineering construction of Sanxia, implement immigrant's policy of the exploration, relevant people's governments organize and lead immigrants to arrange work, use immigrant's funds in a unified manner, exploit natural resources rationally, based on agriculture, the agriculture,industry and commerce combine, through many channel, many industries, multi-form, many method find a room for immigrants properly, immigrants' living standard reach or exceed originally and competently, and create the condition for long-term economic development and improvement of immigrant's living standard of reservoir area of Three Gorges. Immigrant's policy of the exploration, is a great reform of the reservoir immigrants of our country. Policy this, and reservoir area of Three Gorges immigrant put forward at the foundation of pilot project eight year in experience and lessons that immigrant work since new China set up of summarizing. At the beginning of reservoir immigrants in Sanxia, carry out exploration immigrants' principles and policies, insist the country supports, the policy is favourable, each side supports, principle of relying on one's own efforts, appeared by the government, develop local resources in a planned way, expand the capacity of placing, help, offer service of forming a complete set, wide to open up, produce the life way, make it reach " take out offing, goal that so steady as to live, can get rich progressively ". Meanwhile, the country approves reservoir area of Three Gorges as " the open economic region of Sanxia ", enjoy some special policies opening to the outside world in the coastal area, call the immigrants in Sanxia of the developed coordinated cooperation of province and city, immigrant's enterprises and relevant The factor of production has been pushed to the broader large market. The governments at all levels of reservoir area of Three Gorges have issued some development coordinated cooperation, favourable measure inviting outside investment too. Reservoir area immigrant demonstrate with open to urge, develop, in order to develop, urge benign situation that place.2. reorganization and expansion of the immigrants in SanxiaThe reorganization of immigrants in Sanxia and the expansion immigrants in Sanxia are that one involve undertaking that the society of reservoir area reconstruct,resources are recombinated, the recombinating is one of the prominent characteristics of the immigrants in Sanxia, move the fundamental difference duplicated with traditional simple compensation immigrants, former state too. Implement immigrant's policy of the exploration, must demand to combine immigrants to move, reconfigure the factor of production, thus improve the disposition efficiency of resources, form new productivity. Expand while being what is called, expansion of scale, improvement of structure even more, function strengthen improvement of quality. Look with the view of development economics and implement the course of exploration immigrants, it is the course of economic expansion of reservoir area. Exploration immigrants begin from expanding, and ending at realizing expanding, the course that the whole immigrant move and rebuild one's home is running through economic expansion, full of to the yearning that expands in the future. Certainly, in actual operation, should set out from immigrant's reality to pay attention to all, insist reason is expanded.Seven. Investment and benefit questionInvests 90,090 million yuan (1993 price) in investment and the Three Gorges Projects static behavior of benefit question, invests more than about 200 billion yuan dynamically while finishing in project. The investment source of the Three Gorges Projects is as follows, state loan, state-run hydropower station each of price of electricity raise the price 0.4-0.7 fen, power station electric rate income of Ge Zhou Ba, the electric rate income after the power station of Sanxia generates electricity wait for, the country has this financial resources to guarantee to invest in putting in place. About benefit, it is estimated it in ten years after the Three Gorges Projects is built up, total project investment principal and interest, unless including project fee and fee for immigration, can have repaid with electric rate income,it prevent flood, shipping,etc. share make the investment. And the Three Gorges Projects prevent flood, generate electricity, shipping,etc. benefit long-term, and enormous social benefit. Therefore, benefit of the Three Gorges Projects is very great, there is increase slightly to even make the investment, it is very rational too to repay service life to slightly lengthen.三峡水利枢纽工程一、坝址及基本枢纽布置三峡工程大坝坝址选定在宜昌市三斗坪，在已建成的葛洲坝水利枢纽上游约40km处。

Comparison of Design and Analysis of Concrete Gravity DamABSTRACTGravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape, mass and strength of the concrete.The purposes of dam construction may include navigation, flood damage reduction,hydroelectric power generation, fish and wildlife enhancement,water quality,water supply,and recreation.The design and evaluation of concrete gravity dam for earthquake loading must be based on appropriate criteria that reflect both the desired level of safety and the choice of the design and evaluation procedures.In Bangladesh, the entire country is divided into 3 seismic zones, depending upon the severity of the earthquake intensity. Thus, the main aim of this study is to design high concrete gravity dams based on the U.S.B.R. recommendations in seismic zone II of Bangladesh, for varying horizontal earthquake intensities from 0.10 g - 0.30 g with 0.05 g increment to take into account the uncertainty and severity of earthquake intensities and constant other design loads, and to analyze its stability and stress conditions using analytical 2D gravity method and finite element method. The results of the horizontal earthquake intensity perturbation suggest that the stabilizing moments are found to decrease significantly with the increment of horizontal earthquake intensity while dealing with the U.S.B.R. Recommended initial dam section, indicating endanger to the dam stability, thus larger dam section is provided to increase the stabilizing moments and to make it safe against failure. The vertical, principal and shear stresses obtained using ANSYS 5.4 analyses are compared with those obtained using 2D gravity method and found less compares to 2D gravity method, except the principal stresses at the toe of the gravity dam for 0.10 g - 0.15 g. Although, it seems apparently that smaller dam section may be sufficient for stress analyses using ANSYS 5.4, it would not be possible to achieve the required factors of safety with smaller dam section.It is observed during stability analyses that the factor of safety against sliding is satisfied at last than other factors of safety, resulting huge dam section to make it safe against sliding. Thus, it can be concluded that it would not be feasible to construct a concrete gravity dam for horizontal earthquake intensity greater than 0.30 g without changing other loads and or dimension of the dam and keeping provision for drainage gallery to reduce the uplift pressure significantly.Keywords: Comparison Concrete Gravity Dam Dam Failure Design Earthquake Intensity Perturbation Stability and Stress1.IntroductionBasically, a gravity concrete dam is defined as a structure,which is designed in such a way that its own weight resists the external forces. It is primarily the weight of a gravity dam whichprevents it from being overturned when subjected to the thrust of impounded water [1]. This type of structure is durable, and requires very little maintenance. Gravity dams typically consist of a non overflow section(s) and an overflow section or spillway. The two general concrete construction methods for concrete gravity dams are conventional placed mass concrete and RCC. Gravity dams, constructed in stone masonry, were built even in ancient times, most often in Egypt, Greece, and the Roman Empire [2,3].However, concrete gravity dams are preferred these days and mostly constructed. They can be constructed with ease on any dam site, where there exists a natural foundation strong enough to bear the enormous weight of the dam. Such a dam is generally straight in plan, although sometimes, it may be slightly curve. The line of the upstream face of the dam or the line of the crown of the dam if the upstream face in sloping, is taken as the reference line for layout purposes, etc. and is known as the “Base line of the Dam” or the “Axis of the Dam”. When suitable conditions are available, such dams can be constructed up to great heights. The ratio of base width to height of high gravity dams is generally less than 1:1.A typical cross-section of a high concrete gravity dam is shown in Figure . The upstream face may be kept throughout vertical or partly slanting for some of its length. A drainage gallery is generally provided in order to relieve the uplift pressure exerted by the seeping water.Purposes applicable to dam construction may include navigation, flood damage reduction, hydroelectric power generation, fish and wildlife enhancement, water quality, water supply, and recreation.Many concrete gravity dams have been in service for over 50 years, and over this period important advances in the methodologies for evaluation of natural phenomena hazards havecaused the design-basis events for these dams to be revised upwards. Older existing dams may fail to meet revised safety criteria and structural rehabilitation to meet such criteria may be costly and difficult. The identified causes of failure, based on a study of over 1600 dams [4] are: Foundation problems (40%), Inadequate spillway (23%), Poor construction (12%), Uneven settlement (10%), High poor pressure (5%), Acts of war (3%), Embankment slips (2%), Defective ma terials(2%), Incorrect operation (2%), and Earthquakes (1%).Other surveys of dam failure have been cited by [5], who estimated failure rates from 2×10-4to7 ×10-4per damyear based on these surveys.2.LoadsIn the design of gravity concrete, it is essential to determine the loads required in the stability and stress analyses. The forces which may affect the design are: 1) Dead load or stabilizing force; 2) Headwater and tailwater pressures; 3) Uplift; 4) Temperature; 5) Earth and silt pressures; 6) Ice pressure; 7) Earth quake forces; 8) Wind pressure; 9) Subatmospheric pressure; 10) Wave pressure, and 11) Reaction of foundation.The seismic safety of such dams has been a serious concern since damage to the Koyna Dam in India in 1967 which has been regarded as a watershed event in the development of seismic analysis and design of concrete gravity dams all over the world. It is essential that those responsible must implement policies and proce dures to ensure seismic safety of dams through sound professional practices and state-of-the-art in related technical areas. Seismic safety of dams concerns public safety and therefore demands a higher degree of public confidence. The Estimations and descriptions of various forces are provided briefly in the following sections.2.1. Water PressureWater pressure (P) is the most major external force acting on gravity dams. The horizontal water pressure exerted by the weight of water stored on the upstream and downstream sides of the dam can be estimated from the rule of hydrostatic pr essure distribution and can be expressed bywhere, H is the depth of water and w γis the unit weight of water.2.2. Uplift PressureWater seepage through the pores, cracks and fissures of the foundation materials, and water seepage through dam body and then to the bottom through the joints between the body of the dam and its foundation at the base exert an uplift pressure on the base of the dam. According to the [6], the uplift pressure intensities at the heel and toe of the dam should be taken equal to their respective hydrostatic pressures and joined the intensity ordinates by a straight line. When drainage galleries are provided to relieve the uplift, the recommended uplift at the face of the gallery is equal to the hydrostatic pressure at toe plus 1/3rd of the difference between the 221H p w γ=hydrostatic pressures at the heel and the toe, respectively.2.3. Earthquake ForcesAn earthquake produces waves, which are capable of shaking the earth upon which the gravity dams rest, in every possible direction. The effect of an earthquake is, therefore, equivalent to imparting acceleration to the foundations of the dams in the direction in which the wave is traveling at the moment.Generally, an earthquake induces horizontal acceleration (h) and vertical acc eleration (v). The values of these accelerations are generally expressed as per centage of the acceleration due to gravity (g), i.e.,= 0.10 g or 0.20 g, etc. On an average, a value of equal to 0.10 to 0.15 g is generally sufficient for high dams in seismic zones. In extremely seismic regions and in conservative Designs even a value up to 0.30 g may sometimes be adopted [7].Earthquake loadings should be checked for horizontal as well as vertical earth quake accelerations. While earthquake acceleration might take place in any direc tion,the analysis should be performed for the most unfavorable direction.The earthquake loadings used in the design of concrete gravity dams are based on design earthquakes and sitespecific motions determined from seismological eva luation. At a minimum, a seismological evaluation should be performed on all pro jects located in seismic zones 1, 2, and 3 of Bangladesh [8], depending upon the severity of earthquakes.The seismic coefficient method of analysis should be used in determining the resultant location and sliding stability of dams. In strong seismicity areas, a dynamic seismic analysis is required for the internal stress analysis.2.3.1. Effect of Vertical Acceleration (ɑv)A vertical acceleration may either act downward or upward. When it acts in the upward direction, then the foundation of the dam will be lifted upward and becomes closer to the body of the dam, and thus the effective weight of the dam will increase and hence, the stress developed will increase.When the vertical acceleration acts downward, the foundation shall try to move downward away from the dam body; thus, reducing the effective weight and the stability of the dam, and hence is the worst case for design. The net effective weight of the dam is given by (2) where, W is the total weight of the dam, kv is the fraction of gravity adopted for verticalacceleration, such as 0.10 or 0.20, etc. In other words, vertical acceleration reduces the unit weight of the dam material and that of water to (1 – kv) times their original unit weights.2.3.2. Effects of Horizontal Acceleration (ɑh))1(v v k w g k gw w -=-The horizontal acceleration may cause 1) hydrodynamic pressure, and 2) horizontal inertia force.1) Hydrodynamic Pressure: Horizontal acceleration acting towards the reservoir causes a momentary increase in the water pressure, as the foundation and dam acc elerate towards the reservoir and the water resists the movement owing to its ine rtia. According to [9], the amount of this hydrodynamic force (Pe) is given by(3) where, Cm = maximum value of pressure coefficient for a given constant slope = 0.735(0θ/ 90) θ , whereθis the angle in degree, which the upstream face of the dam makes wi th the horizontal; kh = fraction of gravity adopted for horizontal acceleration such as αh=kh ×gThe moment of this force about the base is given by(4) 2) Horizontal Inertia Force: In addition to exerting the hydrodynamic pressure, the horizontal acceleration produces an inertia force into the body of the dam. This force is generated to keep the body and the foundation of the dam together as one piece. The direction of the produced force will be opposite to the accele ration imparted by the earthquake.Since an earthquake may impart either upstream or downstream acceleration, it is needed to choose the direction of this force in the stability analysis of dam structure in such a way that it produces most unfavorable effects under the consid ered conditions. For example, when the reservoir is full, this force will produce worst results if it is additive to the hydrostatic water pressure, thus Acting towards the downstream (i.e., when upstream earthquake acceleration towards the reservoir is produced). When the reservoir is empty, this force would produce worst results, if considered to be acting upstream (i.when earthquake acceleration moving towards the downstream is produced.原文出自：/journal/PaperInformation.aspx?paperID=181852726.0H kC p w h m e γ=H P M e e 412.0=混凝土重力坝的设计分析与比较摘要重力坝是一种坚实的混凝土结构.大坝建设的目的可能包括通航,减少洪水造成的损失,水力发电,鱼类和野生动物养殖,蓄水灌溉等.混凝土重力坝的设计和评估地震荷载必须基于适当的标准,既能反映所需的安全级别，也要有设计的选择和评价程序.在孟加拉国,整个国家被分成3个地震带,这取决于地震强度的严重性.因此,本研究的主要目的是设计基于U.S.B.R高混凝土重力坝.在孟加拉国地震带二区,建议对不同水平地震强度从0.10g～0.30g 和0.50g增量考虑地震烈度，持续的不确定性和严重程度等其他来设计负荷。

Hand Move Irrigation SystemsSummaryThe ‘hand move’ irrigation system is a very simple pipe set which can be moved by hand. Two main factors-—positioning and moving scheme of the equipment both affect the work time. Here we develop a model to complete the irrigation of the whole field by the shortest time。

Firstly, we decide the certain number of sprinklers through the designated parameter。

Using enumerative geometry, we compare the irrigation area of the system with different number of sprinklers and work out the optimum number of sprinklers。

Secondly, we take the advantage of combinatorial geometry to decide the positioning and moving scheme of the irrigation system，in order that the model can be used to realize the irrigation task by the shortest work time.In the end we also introduce a new sprinkler with square area and compare its working efficiency with the traditional sprinkler if we use it on this field。

中英文对照外文翻译(文档含英文原文和中文翻译)Reinforced ConcreteConcrete and reinforced concrete are used as building materials in every country. In many, including the United States and Canada, reinforced concrete is a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete and reinforced concrete are used in bridges, buildings of all sorts underground structures, water tanks, television towers, offshore oil exploration and production structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed in their final location, or they may be precast concreteproduced in a factory and erected at the construction site. Concrete structures may be severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engineer such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whenever loads, or restrained shrinkage of temperature changes, give rise to tensile stresses in excess of the tensile strength of the concrete. In a plain concrete beam, the moments about the neutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beam fails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the concrete in such a way that the tension forces needed for moment equilibrium after the concrete cracks can be developed in the bars.The construction of a reinforced concrete member involves building a from of mold in the shape of the member being built. The form must be strong enough to support both the weight and hydrostatic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies, wind, and so on. The reinforcement is placed in this form and held in place during the concreting operation. After the concrete has hardened, the forms are removed. As the forms are removed, props of shores are installed to support the weight of the concrete until it has reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength to resist the loads and adequate stiffness to prevent excessive deflections. In beam must be proportioned so that it can be constructed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the concrete is placed in the form after the reinforcement is in place, the concrete must be able to flow around, between, and past the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. The choice of structural system is made by the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shape and texture by means of the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearing elements while providing the finished floor and / or ceiling surfaces. Similarly, reinforced concrete walls can provide architecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Finally, the choice of size of shape is governed by the designer and not by the availability of standard manufactured members.3. Fire resistance. The structure in a building must withstand the effects of a fire and remain standing while the building is evacuated and the fire is extinguished. A concrete building inherently has a 1- to 3-hour fire rating without special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratings.4. Low maintenance.Concrete members inherently require less maintenance than do structural steel or timber members. This is particularly true if dense, air-entrained concrete has been used forsurfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are very widely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume.The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled,and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course in strength of materials for homogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because unreinforced concrete is brittle, it cannot undergo large deformations under load and failssuddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to cover construction in a given region, often a city or a state. The objective of a building code is also to protect the public by accounting for the influence of the local environmental conditions on construction. For example, local authorities may specify additional provisions to account for such regional conditions as earthquake, heavy snow, or tornados. National structural codes genrally are incorporated into local building codes.The American Concrete Institute ( ACI ) Building Code covering the design of reinforced concrete buildings. It contains provisions covering all aspects of reinforced concrete manufacture, design, and construction. It includes specifications on quality of materials, details on mixing and placing concrete, design assumptions for the analysis of continuous structures, and equations for proportioning members for design forces.All structures must be proportioned so they will not fail or deform excessively under any possible condition of service. Therefore it is important that an engineer use great care in anticipating all the probableloads to which a structure will be subjected during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the forces produced by wind, impact, shrinkage, temperature change, creep and support settlements, earthquake, and so forth.The load associated with the weight of the structure itself and its permanent components is called the dead load. The dead load of concrete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately until members have been sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the members sized, and architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initial estimate of its value ( or slightly less ), the design is complete, but if a significant difference exists between the computed and estimated values of dead weight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly important when spans are long, say over 75 ft ( 22.9 m ), because dead load constitutes a major portion of the design load.Live loads associated with building use are specific items of equipment and occupants in a certain area of a building, building codes specify values of uniform live for which members are to be designed.After the structure has been sized for vertical load, it is checked for wind in combination with dead and live load as specified in the code. Wind loads do not usually control the size of members in building less than 16 to 18 stories, but for tall buildings wind loads become significant and cause large forces to develop in the structures. Under these conditions economy can be achieved only by selecting a structural system that is able to transfer horizontal loads into the ground efficiently.钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。

混凝土重力坝中英文资料外文翻译文献混凝土重力坝基础流体力学行为分析摘要：一个在新的和现有的混凝土重力坝的滑动稳定性评价的关键要求是对孔隙压力和基础关节和剪切强度不连续分布的预测。

本文列出评价建立在岩石节理上的混凝土重力坝流体力学行为的方法。

该方法包括通过水库典型周期建立一个观察大坝行为的数据库，并用离散元法（DEM）数值模式模拟该行为。

一旦模型进行验证，包括岩性主要参数的变化，地应力，和联合几何共同的特点都要纳入分析。

斯威土地，Albigna 大坝坐落在花岗岩上，进行了一个典型的水库周期的特定地点的模拟，来评估岩基上的水流体系的性质和评价滑动面相对于其他大坝岩界面的发展的潜力。

目前大坝基础内的各种不同几何的岩石的滑动因素，是用德国马克也评价模型与常规的分析方法的。

裂纹扩展模式和相应扬压力和抗滑安全系数的估计沿坝岩接口与数字高程模型进行了比较得出，由目前在工程实践中使用的简化程序。

结果发现，在岩石节理，估计裂缝发展后的基础隆起从目前所得到的设计准则过于保守以及导致的安全性过低，不符合观察到的行为因素。

关键词：流体力学，岩石节理，流量，水库设计。

简介：评估抗滑混凝土重力坝的安全要求的理解是，岩基和他们上面的结构是一个互动的系统，其行为是通过具体的材料和岩石基础的力学性能和液压控制。

大约一个世纪前，Boozy大坝的失败提示工程师开始考虑由内部产生渗漏大坝坝基系统的扬压力的影响，并探讨如何尽量减少其影响。

今天，随着现代计算资源和更多的先例，确定沿断面孔隙压力分布，以及评估相关的压力和评估安全系数仍然是最具挑战性的。

我们认为，观察和监测以及映射对大型水坝的行为和充分的仪表可以是我们更好地理解在混凝土重力坝基础上的缝张开度，裂纹扩展，和孔隙压力的发展。

图.1流体力学行为：（一）机械;（二）液压。

本文介绍了在过去20个来自Albigna大坝，瑞士，多年收集的水库运行周期行为的代表的监测数据，描述了一系列的数值分析结果及评估了其基础流体力学行为。

水利电力英文翻译英文+中文An overflow spillway is a section of dam designed to permit water to pass over its crest. Overflow spillways are widely used on gravity, arch, and buttress dams. Some earth dams have a concrete gravity section designed to serve as a spillway. The design of the spillway for tow dams is not usually critical, and a variety of simple crest patterns are used. In the case of large dams it is important that the overflowing water be guided smoothly over the crest with a minimum of turbulence. If the overflowing water breaks contact with the spillway surface, a vacuum will form at the point of separation and cavitations may occur. Cavitations plus the vibration from the alternates making and breaking of contact between the water and the face of the dam may result in serious structural damage.Cavities filled with vapor, air, and other gases will form in a liquid whenever the absolute pressure of the liquid is close to the vapor pressure. This phenomenon, cavitations, is likely to occur where high velocities cause reduced pressure. Such conditions may arise if the walls of a passage are so sharply curved as to cause separation of flow from the boundary. The cavity, on moving downstream, may enter a region where the absolute is much higher. This causes the vapor in the cavity to condense and return to liquid with a resulting implosion, or collapse, extremely high pressure result. Some of the implosive activity will occur at the surfaces of the passage and in the crevices and pores of the boundary material. Under a continual bombardment of these implosions, the surface undergoes fatigue failure and small particles are broken away, giving the surface a spongy appearance. This damaging action of cavitations is called pitting. The ideal spillway would take the form of the underside of the napped of a sharp-crested weir when the flow rate corresponds to the maximum design capacity of the spillway. More exact profiles may be found in more extensive treatments of the subject. The reverse curve on the downstream face of the spillway should be smooth and gradual; A radius of about one-fourth of the spillway height has proved satisfactory. Structural design of an ogee spillway is essentially the same as the design of a concrete gravity section. The pressure exerted on the crest of the spillway by the flowing water and the drag forces caused by fluid friction are usually small in comparison with the other forces acting on the section. The change in momentum of the flow in the vicinity of the reverse curve may, however, create a force which must be considered. The requirements of the ogee shape usually necessitate a thicker section than the adjacent no overflow sections.A saving of concrete can be effected by providing a projecting corbel on the upstream face to control the flow in outlet conduits through the dam, a corbel will interfere with gate operation. The discharge of an overflow spillway is given by the weir equation23C Q Lh ω= Where Q=discharge, or sec /3mt coefficien C =ωL=coefficienth=head on the spillway (vertical distance from the crest of the spillway to the reservoir level),mThe coefficient ωC varies with the design and head. Experimental models are often used to determine spillway coefficient. End contractions on a spillway reduce the effective length below the actual length L. Square-cornered piers disturb the flow considerably and reduce the effective length by the width of the piers plus about 0.2h for each pier.Streamlining the piers or flaring the spillway entrance minimizes the flow disturbance. If the cross-sectional area of the reservoir just upstream from the spillway is less than five times the area of flow over the spillway, the approach velocity with increase the discharge a noticeable amount. The effect of approach velocity can be accounted for by the equation2320g 2V h Q ⎪⎪⎭⎫ ⎝⎛+=L C ωwhere 0V is the approach velocity.PROPERTIES OF CONCRETEThe characteristics of concrete should be considered in relation to the quality for any given construction purpose. The closest practicable approach to perfection in every property of the concrete would result in poor economy under many conditions, and the most desirable structure is that in which the concrete has been designed with the correct emphasis on each of the various properties of the concrete, and not solely with a view to obtaining, say, the maximum possible strength.Although the attainment of the maximum strength should not be the sole criterion in design, the measurement of the crushing strength of concrete cubes or cylinders provides a means of maintaining a uniform standard of quality, and, in fact, is the usual way of doing so. Since the other properties of any particular mix of concrete are related to the crushing strength in some manner, it is possible that as a single control test it is still the most convenient and informative. The testing of the hardened concrete in prefabricated units presents no difficulty, since complete units can be selected and broken if necessary in the process of testing. Samples can be taken from some parts of a finished structure by cutting cores, but at consider one cost and with a possible weakening of the structure. It is customs, therefore, to estimate the properties of the concrete in the structure on the oasis of the tests made on specimens mounded from the fresh concrete as it is placed. These specimens are compacted and cured in a standard manner given in BS 1881 in 1970 as in these two respects it is impossible to simulate exactly the conditions in the structure. Since the crushing structure is also affected by the size and shape of a specimen or part of a structure, it follows that the crushing strength of a cube is not necessary the same as that of the mass of exactly the same concrete.Crushing strengthConcrete can be made having a strength in compression of up to about 80N/2mm ,or evenmore depending mainly on the relative proportions of water and cement, that is, the water/cement ratio, and the degree of compaction. Crushing strengths of between 20 and 50 mm at 28 days are normally obtained on the site with reasonably good supervision, for N/2mixes roughly equivalent to 1:2:4 of cement: sand: coarse aggregate. In some types of precastmm at 28 days are concrete such as railway sleepers, strengths ranging from 40 to 65 N/2obtained with rich mixes having a low water/cement ratio.The crushing strength of concrete is influenced by a number of factors in addition to the water/cement ratio and the degree of compaction. The more important factors are Type of cement and its quality. Both the rate of strength gain and the ultimate strength may be affected.Type and surface texture of aggregate. There is considerable evidence to suggest that some aggregates produce concrete of greater compressive and tensile strengths than obtained with smooth river gravels.Efficiency of curing. A loss in strength of up to about 40 per cent may result from premature drying out. Curing is therefore of considerable, importance both in the field and in the making of tests. The method of curing concrete test cubes given in BS 1881 should, for this reason, be strictly adhered to.Temperature In general, the rate of hardening of concrete is increased by an increase temperature. At freezing temperatures the crushing strength may remain low for some time.Age Under normal conditions increase in strength with age, the rate of increase depending on the type of cement with age. For instance, high alumina cement produces concrete with a crushing strength at 21 hours equal to that of normal Portland cement concrete at 28 days. Hardening continues but at a much slower rate for a number of years.The above refers to the static ultimate load. When subjected to repeated loads concrete fails at a load smaller than the ultimate static load, a fatigue effect. A number of investigators have established that after several million cycles of loading, the fatigue strength in compression is 50-60 per cent of the ultimate static strength.Tensile and flexural strengthThe tensile strength of concrete varies from one-eighth of the compressive strength at early ages to about one- twentieth later, and is not usually taken into account in the design of reinforced concrete structures. The tensile strength is, however, of considerable importance in resisting cracking due to changes in moisture content or temperature. Tensile strength tests are used for concrete roads and airfields.The measurement of the strength of concrete in direct tension is difficult and is rarely attempted. Two more practical methods of assessing tensile strength are available. One gives a measure of the tensile strength in bending, usually termed the flexural strength. BS 1881:1970 gives details concerning the making and curing of flexure test specimens, and of the method test. The standard size of specimen is 150m m×150m m×750m m long for aggregate of maximum size 40m m. If the largest nominal size of the aggregate is 20m m, specimens 100m m×100m m×750m m long may be used.A load is applied through two rollers at the third points of the span until the specimen breaks. The extreme fiber stresses, that is, compressive at the top and tensile at the bottom, can then be computed by the usual beam formulae. The beam will obviously fail in tension since the tensile strength is much lower than the compressive strength. Formulae for the calculation of the modulus of rupture are given in BS 1881:1970.Test specimens is the form of beams are sometimes used to measure the modulus of rupture or flexural strength quickly on the site. The two halves of the specimen may then be crushed so that besides the flexural strength the compressive strength can be approximately determined on the same sample. The test is described in BS 1881:1970.Values of the modulus of rupture are utilized in some methods of design of unreinforced concrete roads and runways, in which reliance is placed on the flexural strength of the concrete to distribute concentrated loads over a wide area.More recently introduced is a test made by splitting cylinders by compression across the diameter, to give what is termed the splitting tensile strength; Details of the method are given in BS 1881:1970.Values of the modulus of rupture are utilized in some methods of design of unreinforced concrete roads and runways, in which reliance is place on the flexural strength of the concrete to distribute concentrated loads over a wide area.More recently introduced is a test made by splitting cylinders by compression across the diameter, to give what is termed the splitting tensile strength; Details of the method are given in BS 1881:1970. the testing machine is fitted with an extra bearing bar to distribute the load along the full length of the cylinder Plywood strips, 12mm wide and 3mm thick are inserted between the cylinder and the testing machine bearing surfaces top and bottom.From the maximum applied load at failure the tensile splitting strength is calculated as follows:ld p 2f t π= Where =t f splitting tensile strength, N/2mmP=maximum applied load in Nl=length of cylinder in mmd=diameter in mmAs in the case of the compressive strength, repeated loading reduces the ultimate strength so that the fatigue strength in flexure is 50-60 per cent of the static strength.Shear strengthIn practice, shearing of concrete is always accompany compression and tension caused by bending, and even in testing is impossible to staminate an element of bending.RESERVOIRSWhen a barrier is constructed across some river in the form of a dam, water gets stored up on the upstream side of the barrier, forming a pool of water, generally called a reservoir.Broadly speaking, any water collected in a pool or a lake may be termed as a reservoir. The water stored in reservoir may be used for various purposes. Depending upon the purposes served, the reservoirs may be classified as follows:Storage or Conservation Reservoirs.Flood Control Reservoirs.Distribution Reservoirs.Multipurpose reservoirs.(1) Storage or Conservation Reservoirs. A city water supply, irrigation water supply or a hydroelectric project drawing water directly from a river or a stream may fail to satisfy the consumers’demands during extremely low flows, while during high flows; it may become difficult to carry out their operation due to devastating floods. A storage or a conservation reservoir can retain such excess supplies during periods of peak flows and can release them gradually during low flows as and when the need arise.Incidentally, in addition to conserving water for later use, the storage of flood water may also reduce flood damage below the reservoir. Hence, a reservoir can be used for controlling floods either solely or in addition to other purposes. In the former case, it is known as ‘Flood Control Reservoir’or ‘Single Purpose Flood Control Reservoir’, and in the later case, it is called a ‘Multipurpose Reservoir’.(2) Flood Control Reservoirs A flood control reservoir or generally called flood-mitigation reservoir, stores a portion of the flood flows in such a way as to minimize the flood peaks at the areas to be protected downstream. To accomplish this, the entire inflow entering the reservoir is discharge till the outflow reaches the safe capacity of the channel downstream. The inflow in excess of this rate is stored in stored in the reservoir, which is then gradually released so as to recover the storage capacity for next flood.The flood peaks at the points just downstream of the reservoir are thus reduced by an amount AB. A flood control reservoir differs from a conservation reservoir only in its need for a large sluice-way capacity to permit rapid drawdown before or after a flood.Types of flood control reservoirs. There are tow basic types of flood-mitigation reservoir.Storage Reservoir or Detention basins.Retarding basins or retarding reservoirs.A reservoir with gates and valves installation at the spillway and at the sluice outlets is known as a storage-reservoir, while on the other hand, a reservoir with ungated outlet is known as a retarding basin.Functioning and advantages of a retarding basin:A retarding basin is usually provided with an uncontrolled spillway and an uncontrolled orifice type sluiceway. The automatic regulation of outflow depending upon the availability of water takes place from such a reservoir. The maximum discharging capacity of such a reservoir should be equal to the maximum safe carrying capacity of the channel downstream. As flood occurs, the reservoir gets filled and discharges through sluiceways. As the reservoir elevation increases, outflow discharge increases. The water level goes on rising until the flood has subsided and the inflow becomes equal to or less than the outflow. After this, water gets automatically withdrawn from the reservoir until the stored water is completely discharged. The advantages of a retarding basin over a gate controlled detention basin are:①Cost of gate installations is save.②There are no fates and hence, the possibility of human error and negligence in their operation is eliminated.Since such a reservoir is not always filled, much of land below the maximum reservoir level will be submerged only temporarily and occasionally and can be successfully used for agriculture, although no permanent habitation can be allowed on this land.Functioning and advantages of a storage reservoir:A storage reservoir with gated spillway and gated sluiceway, provides more flexibility of operation, and thus gives us better control and increased usefulness of the reservoir. Storage reservoirs are, therefore, preferred on large rivers which require batter controlled and regulated properly so as not to cause their coincidence. This is the biggest advantage of such a reservoir and outweighs its disadvantages of being costly and involving risk of human error in installation and operation of gates.(3) Distribution Reservoirs A distribution reservoir is a small storage reservoir constructed within a city water supply system. Such a reservoir can be filled by pumping water at a certain rate and can be used to supply water even at rates higher than the inflow rate during periods of maximum demands (called critical periods of demand). Such reservoirs are, therefore, helpful in permitting the pumps or water treatment plants to work at a uniform rate, and they store water during the hours of no demand or less demand and supply water from their ‘storage’during the critical periods of maximum demand.(4) Multipurpose Reservoirs A reservoir planned and constructed to serve not only one purpose but various purposes together is called a multipurpose reservoir. Reservoir, designed for one purpose, incidentally serving other purpose, shall not be called a multipurpose reservoir, but will be called so, only if designed to serve those purposes also in addition to its main purpose. Hence, a reservoir designed to protect the downstream areas from floods and also to conserve water for water supply, irrigation, industrial needs, hydroelectric purposes, etc. shall be called a multipurpose reservoir.THE ELECTRIC POWER SYSTEMA great amount of effort is necessary to maintain an electric power supply within the requirement of the various types of customers served. Large investments are necessary, and continuing advancements in methods must be made as loads steadily increase from year to year. Some of the requirements for electric power supply are recognized by most consumers, such as proper voltage, availability of power on demand, reliability, and reasonable cost. Other characteristics, such as frequency, wave shape, and phase balance, are seldom recognized by the customer but are given constant attention by the utility power engineers.The voltage of the power supply at the customer’s service entrance must be held substantially constant. Variations in supply voltage are, from the customer’s view, detrimental in various respects. For example, below-normal voltage substantially reduces the light output from incandescent lamps. Above-normal voltage increase the light output but substantially reduces the life of the lamp. Motor operate at below-normal voltage draw abnormally high current and may overheat, even when carrying no more than the rated horsepower load. Over voltage on a motor may cause excessive heat loss in the iron of the motor, wasting energy and perhaps damaging the machine. Service voltages are usually specified by a nominal value and the voltage thanmaintained close to this value, deviating perhaps less than 5 percent above or below the nominal value. For example, in a 120-volt residential supply circuit, the voltage might normally vary between the limits of 115 and 125 volts as customer load and system conditions change throughout the day.Power must be available to the consumer in any amount that be may require from minute to minute. For example, motors may be turned on or off, without advance warning to the electric power company. As electrical energy cannot be stored (except to a limited extent in storage batteries), the changing loads impose severe demands on the control equipment of any electrical power system. The operating staff must continually study load patterns to predict in advance those major load changes that follow known schedules, such as the starting and shutting down of factories at prescribed hours each day.The demands for reliability of service increase daily as our industrial and social environment becomes more complex. Modern industry is almost locally dependent on electric power for its operation. Homes and office buildings are lighted, heated, and ventilated by electric power. In some instances loss of electric power may even pose a threat a life itself. Electric power, like everything else that is man-made can never be absolutely reliable. Occasional interruptions to service in limited areas will continue. Interruptions to large areas remain a possibility, although such occurrences may be very infrequent. Further interconnection of electric supply systems over wide areas, continuing development of reliable automated control systems and apparatus; provision of additional reserve facilities; and further effort in developing personnel to engineer, design, construct, maintain, and operate these facilities will continue to improve the reliability of the electric power supply.The cost of electric power is a prince consideration in the design and operation of electric power is a prime consideration in the design and operation of electric power system. Although the cost of almost all commodities has risen steadily over the past many years, the cost per kilowatt-hour of electrical energy has actually declined. This decrease in cost has been possible because of improved efficiencies of the generating stations and distribution systems. Although franchises often grant the electric power company exclusive rights for the supply of electric power to an area. There is keen competition between electric power and other forms of energy, particularly for heating and for certain heavy load industrial processes.The power supply requirements just discussed are all well known to most electric power users. There are, however, other specifications to the electric power supply which are so effectively handled by the power companies that consumers are seldom aware that such requirements are of importance.The frequency of electric power supply in the United States is almost entirely 60 hertz (formerly cycles per second). The frequency of a system is dependent entirely upon the speed at which the supply generator is rotated by its prime mover. Hence frequency control is basically a matter of speed control of the machines in the generating stations. Modern speed-control systems are very effective and hold frequency almost constant. Deviations are seldom greater than 0.02 hertz.In an ac system the voltage continually varies with time, at one instant being positive and a short time later being negative, going through 60 complete cycles of change in each second. Ideally a plot of the time change should be a sine wave.In poorly designed generating equipment, harmonics may be present and the wave shape maybe somewhat. The presence of harmonics produces unnecessary losses in the customer’s equipment and sometime produces hum in nearby telephone lines. The voltage wave shape is basically determined by the construction of the generation equipment. The power companies put specification limitations on the harmonic content of generator voltages and so require equipment manufactures to design and build their machines to minimize from this effect.ENVIRONMENT POLLUTIONThe existence of pollution in the environment, as a national and a world problem, was not generally recognized until the 1960s.Today many people regard pollution as a problem that will not go away, but one that could get worse in the future. It is increasingly being appreciated that the general effects of pollution produce a deterioration of the quality of the environment. This usually means that pollution is responsible for dirty streams, rivers and sea shorts, atmospheric contamination, the dissociation of the countryside, urban dereliction, affecting the environment in which people reside, work, and spend their leisure time.The present increasing emphasis upon pollution may create the impression that there has been a relatively sudden deterioration of the environment, that was not apparent twenty or thirty years ago. This is not the case. Pollution must have started at the time when man began to use the natural resources of the environment for his own benefit. At he began to develop a settled life in small communities, the activities of clearing trees, building shelter, cultivating crops, and preparing and cooking food must have altered the natural environment. Later, as the human population increased and became concentrated into large communities which developed craft skills. There were increasing quantities of human and animal waste and rubbish to be disposed of in the early days of man’s existence the amount of waste was small. It was disposed of locally and had virtually no effect upon the environment. Later, when large human settlements and towns were established, waste disposal began to cause obvious pollution of streets and water courses. In the thirteenth century the prevalence of cholera, typhus, typhoid and bubonic plague was associated with the lack of proper waste disposal methods. By themed-nineteenth century the population of the UK had increased to 22 million, and many canals and rivers were grossly polluted with sewage and industrial waste. Some sewerage systems existed in towns, but the collected sewage was discharged into the nearest river without ant treatment. Salmon had completely disappeared from the River Thames and outbreaks of cholera still occurred in London. A Royal Commission on the Prevention of River Pollution was established in 1857, and eventually the first preventive river pollution legislation was passed in 1876 and 1890. However, there was little significant improvement in pollution until after the First World War, and the condition of rivers had deteriorated again by the end of the Second World War. Even today, a number of British and continental coastal towns discharge almost untreated sewage into near-shore waters.The increasing pollution of land water was accompanied by air pollution. This must have begun as soon as man started to use wood fires to provide ‘space hosting’and a means of cooking food. Later surface, soft coal was discovered and used as a fuel, and records shown that coal smokes was a nuisance in London in the thirteenth century. In 1273,Edward I made the first ever anti-pollution law to prevent the use of coal for domestic heating, so smoke pollution has been recognized for at least 700 years. However, smoke pollution in London continued and isrecorded in both the sixteenth and seventeenth centuries. In the late eighteenth and throughout the nineteenth centuries there was a marked increase in air pollution, because of the greater use of coal by developing industry. From 1750, the chemical industry began to develop, and this caused the discharge of acid fumes into the smoky air of some manufacturing towns. A Royal Commission was set up in 1862 to consider air pollution and this resulted in the first Alkali Act in 1863, which set limits to the concentration of acid in discharged waste gases. However, the increasing domestic and industrial combustion of coal, and the production of piped coal gas from 1815, caused air pollution to steadily get worse. Large cities were particularly affected, and the well known 5 day smog incident in London in 1952 directly contributed to the deaths of 4000 people. As a result, the Beaver Committee on Air Pollution was established in 1953, and the Clean Air Act was passed in 1956. This was the first effective statute to provide the means of controlling atmospheric pollution.Noise pollution probably started when man first developed machines. The increase in industrial plants in the nineteenth century produce indoor noise pollution of the working environment for many factory and mill workers over a 6 day week. Outdoors, the development of private and public transport bright environmental noise, as the railway services came into use during the 1830s, motor transport from 1900, and regular aero plane services from 1922. during the first half of the twentieth century environmental noise considerably increased, but it was not recognized as pollution. Industrial and outdoor noise was designated as ‘nuisance’when the Noise Abatement Act was passed in 1960. Whereas the earlier increase in noise occurred in work places and in connection with transport, during the past thirty years noise has spread into the home and places of leisure and entertainment. Certainly the most rapid increase in environmental pollution has taken place during the last 150 years, and it has been attributed to a number of interrelating factors.THE CHARACTERISTICS OF FLUIDSA fluid is a substance which may flow, that is, its constituent particles may continuously change their positions relative to one another. Moreover, it offers no lasting resistance to the displacement, however great, of one layer over another. This means that, if the fluid is at rest, no shear force (that is a force tangential to the surface on which it acts) can exist in it. A solid, on the other hand, can resist a shear force while at rest, the shear force may cause some displacement of one layer over another, but the material does not continue to move indefinitely. In a fluid, however, shear forces are possible only while relative movement between layers is actually taking place. A fluid is further distinguished from a solid in that a given amount of it owes its shape at any particular time to that of a vessel containing it, or to forces which in some way restrain its movement.The distinction between solids and fluids is usually clear, but there are some substances not easily classified. Some fluids, for on the ground, but, although its flow would take place very slowly, yet over a period of time—perhaps several days—it would spread over the ground by the action of gravity, that is ,its constituent particle would change their relative positions. In the other hand, certain solids may be made to ‘flow’ when a sufficiently large force is applied, there are known as plastic solids.Even so, the essential difference between solids and fluids remains. Any fluid, no matter how。

毕业设计（论文）外文文献翻译文献、资料中文题目：土石坝的评估和修复文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14附录一外文翻译英文原文Assessment and Rehabilitation of Embankment DamsNasim Uddin, P.E., M.ASCE1Abstract:A series of observations, studies, and analyses to be made in the field and in the office are presented to gain a proper understanding of how an embankment dam fits into its geologic setting and how it interacts with the presence of the reservoir it impounds. It is intended to provide an introduction to the engineering challenges of assessment and rehabilitation of embankments, with particular reference to a Croton Dam embankment.DOI: 10.1061/(ASCE)0887-3828(2002)16:4(176)CE Database keywords: Rehabilitation; Dams, embankment; Assessment.IntroductionMany major facilities, hydraulic or otherwise, have become very old and badly deteriorated; more and more owners are coming to realize that the cost of restoring their facilities is taking up a significant fraction of their operating budgets. Rehabilitation is, therefore, becoming a major growth industry for the future. In embankment dam engineering, neither the foundation nor the fills arepremanufactured to standards or codes, and their performance correspondingly is never 100% predictable. Dam engineering—in particular, that related to earth structures—has evolved on many fronts and continues to do so, particularly in the context of the economical use of resources and the determination of acceptable levels of risk. Because of this, therefore, there remains a wide variety of opinion and practice among engineers working in the field. Many aspects of designing and constructing dams will probably always fall within that group of engineering problems for which there are no universally accepted or uniquely correct procedures.In spite of advances in related technologies, however, it is likely that the building of embankments and therefore their maintenance, monitoring, and assessment will remain an empirical process. It is, therefore, difficult to conceive of a set of rigorous assessment procedures for existing dams, if there are no design codes. Many agencies (the U.S. Army Corps of Engineers, USBR, Tennessee Valley Authority, FERC, etc.) have developed checklists for field inspections, for example, and suggested formats and topics for assessment reporting. However, these cannot be taken as procedures; they serve as guidelines, reminders, and examples of what to look for and report on, but they serve as no substitute for an experienced, interested, and observant engineering eye. Several key factors should be examined by the engineer in the context of the mandate agreed upon with the dam owner, and these together with relevant and appropriate computations of static and dynamic stability form the basis of the assessment. It is only sensible for an engineer to commit to the evaluation of the condition of, or the assessment of, an existing and operating dam if he/she is familiar and comfortable with the design and construction of such things and furthermore has demonstrated his/her understanding and experience.Rehabilitation MeasuresThe main factors affecting the performance of an embankment dam are (1)seepage; (2)stability; and (3) freeboard. For an embankment dam, all of these factors are interrelated. Seepage may cause erosion and piping, which may lead to instability. Instability may cause cracking, which, in turn, may cause piping and erosion failures. The measures taken to improve the stability of an existing dam against seepage and piping will depend on the location of the seepage (foundation or embankment), the seepage volume, and its criticality. Embankment slope stability is usually improved by flattening the slopes or providing a toe berm. This slope stabilization is usually combined with drainage measures at the downstream toe. If the stability of the upstream slope under rapid drawdown conditions is of concern, then further analysis and/or monitoring of resulting pore pressures or modifications of reservoir operationsmay eliminate or reduce these concerns. Finally, raising an earth fill dam is usually a relatively straightforward fill placement operation, especi ally if the extent of the raising is relatively small. The interface between the old and new fills must be given close attention both in design and construction to ensure the continuity of the impervious element and associated filters. Relatively new materials, such as the impervious geomembranes and reinforced earth, have been used with success in raising embankment dams. Rehabilitation of an embankment dam, however, is rarely achieved by a single measure. Usually a combination of measures, such as the installation of a cutoff plus a pressure relief system, is used. In rehabilitation work, the effectiveness of the repairs is difficult to predict; often, a phased approach to the work is necessary, with monitoring and instrumentation evaluated as the work proceeds. In the rehabilitation of dams, the security of the existing dam must be an overriding concern. It is not uncommon for the dam to have suffered significantdistress—often due to the deficiencies that the rehabilitation measures are to address.The dam may be in poor condition at the outset and may possibly be in a marginally stable condition. Therefore, how the rehabilitation work may change the present conditions, both during construction and in the long term, must be assessed, to ensure that it does not adversely affect the safety of the dam. In the following text, a case study is presented as an introduction to the engineering challenges of embankment rehabilitation, with particular reference to the Croton Dam Project.Case StudyThe Croton Dam Project is located on the Muskegon River in Michigan. The project is owned and operated by the Consumer Power Company. The project structures include two earth embankments, a gated spillway, and a concrete and masonry powerhouse. The earth embankments of this project were constructed of sand with concrete core walls. The embankments were built using a modified hydraulic fill method. This method consisted of dumping the sand and then sluicing the sand into the desired location. Croton Dam is classified as a ‗‗h igh-hazard‘‘ dam and is in earthquake zone 1. As part of the FERC Part 12 Inspection (FERC 1993), an evaluation of the seismic stability was performed for the downstream slope of the left embankment at Croton Dam. The Croton Dam embankment was analyzed in the following manner. Soil parameters were chosen based on standard penetration (N) values and laboratory tests, and a seismic study was carried out to obtain the design earthquake. Using the chosen soil properties, a static finite-element study was conducted to evaluate the existing state of stress in the embankment. Then a one-dimensional dynamic analysis was conducted to determine the stress induced by the design earthquake shaking. The available strength was compared withexpected maximum earthquake conditions so that the stability of the embankment during and immediately after an earthquake could be evaluated. The evaluation showed that theembankment had a strong potential to liquefy and fail during the design earthquake. The minimum soil strength required to eliminate the liquefaction potential was then determined, and a recommendation was made to strengthen the embankment soils by insitu densification.Seismic EvaluationTwo modes of failure were considered in the analyses—namely, loss of stability and excessive deformations of the embankment. The following analyses were carried out in succession: (1) Determination of pore water pressure buildup immediately following the design earthquake; (2) estimation of strength for the loose foundation layer during and immediately following the earthquake; (3) analysis of the loss of stability for postearthquake loading where the loose sand layer in the embankment is completely liquefied; and (4) liquefaction impact analysis for the loose sand layer for which the factor of safety against liquefaction is unsatisfactory.Liquefaction Impact AssessmentBased on the average of the corrected SPT value and cyclic stress ratio (Tokimatsu and Seed 1987), a total settlement of the 4.6 m(15 ft) thick loose embankment layer due to complete liquefaction was found to be 0.23 m (0.75 ft).Permanent Deformation AnalysisBased on a procedure by Makdisi and Seed (1977), permanent deformation can be calculated using the yield acceleration, and the time history of the averagedinduced acceleration. Since the factor of safety against flow failure immediately following theearthquake falls well short of that required by FERC, the Newmark type deformation analysis is unnecessary. Therefore, it can be concluded that the embankment will undergo significant permanent deformation following the earthquake, due to slope failure in excess of the liquefaction-induced settlement of 0.23 m (0.75ft).Embankment RemediationBased on the foregoing results, it was recommended to strengthen the embankment by in situ densification. An analysis was carried out to determine the minimum soil strength required to eliminate the liquefaction potential. The analysis was divided into three parts, as follows. First, a slope stability analysis @using the computer program PCSTABL (Purdue 1988)# of the downstream slope of the left embankment was conducted. Strength and geometric parameters were varied in order to determine the minimum residual shear strength and minimum zone of soil strengthening required for a postearthquake stability factor of safety, (FS)>1.Second, SPT corrections were made. The minimum residual shear strength correlates to a corrected/normalized penetrationresistance value (N1) of 60. From this value, a backcalculation was performed to determine the minimum field measure standard penetration resistance N values (blows per foot). Third, liquefaction potential was reevaluated based on the minimum zone of strengthening and minimum strength in order to show that if the embankment is strengthened to the minimum value, then the liquefaction potential in the downstream slope of the left embankment will, for all practical purposes, be eliminated.ConclusionKey factors to be considered in dam assessment and rehabilitation are the completeness of design, construction, maintenance and monitoring records, and the experience, background, and competence of the assessing engineer. The paper presents a recently completed project to show that the economic realization of this type of rehabilitation inevitably rests to a significant degree upon the expertise of the civil engineers.ReferencesDuncan, J. M., Seed, R. B., Wong, K. S., and Ozawa, U. (1984). ‗‗FEADAM: A computer program for finite element analysis of dams.‘‘ GeotechnicalEngineering Research Rep. No. SU/GT/84-03,Dept. of Civil Engineering,Stanford Univ., Stanford, Calif.FERC. (1993). ‗‗Engineering guidelines for the evaluation of hydropower projects.‘‘ 0119-2.Makdisi, F. I., and Seed, H. B. (1977). ‗‗A simplified procedure forestimatingea rthquake induced deformations in dams and embankments.‘‘ Rep. No. EERC 77-19, Univ. of California, Berkeley, Calif.Purdue Univ. (1988). ‗‗PCSTABL: A computer program for slope stability analysis.‘‘ Rep., West Lafayette, Ind.Schnabel, P. B., Lysmer, J, an d Seed, H. B. (1972). ‗‗SHAKE: A computer program for earthquake response analysis of horizontally layered site.‘‘ Rep. No. EERC72-12, Univ. of California, Berkeley, Calif.Seed and Harder. (1990). ‗‗An SPT-based analysis of cyclic pore pressure generation and undrained residual strength.‘‘ Proc., H. Bolton Seed Memorial Symp., 2, 351–376.Tokimatsu, K., and Seed, H. B. (1987). ‗‗Evaluation of settlements of sands due to earthquake shaking.‘‘ J. Geotech. Eng., 113(8), 861–878.中文翻译土石坝的评估和修复摘要：在野外实地、办公室里已进行的一系列的观察，研究，分析，使本文获得了对石坝如何适应其地质环境，以及如何与水库相互影响的正确的认识。

水利工程三峡水利枢纽工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)The Three Gorges ProjectsFirst. The dam site and basic pivot disposalThe Three Gorges Projects is select to be fixed on San Dou Ping in Yichang, located in about 40 kilometers of the upper reaches of key water control project of Ge Zhou Ba which was built. River valley, district of dam site, is widen, slope, the two sidesof the bank is relatively gentlely. In the central plains have one island (island, fort of China,), possess the good phased construction water conservancy diversion condition. The foundation of pivot building is the hard and intact body of granite. Have built Yichang and gone to stride bridge that place of 4 kilometers in the about 28 -km-long special-purpose expressway of building site and dam low reaches --West Yangtze Bridge of imperial tomb. Have also built the quay of district of a batch of dams. The dam district possesses the good traffic condition.Two. Important water conservancy project buildings1. damThe dam is a concrete gravity dam, which is 2309 meters long, it’s height is 185meters , the dam is 181 meters high the most. Release floodwater dam section lie riverbed, 483 of the total length, consist of 22 form hole and 23 release floodwater in the deep hole, among them deep hole is imported 90 meters , the mouth size of hole is 7*9 meters; Form hole mouth is 8 meter wide, overflow weir is 158 meters, form hole and deep hole adopt nose bank choose, flow way go on and can disappear. Dam section lies in and releases floodwater on a section of both sides of the dam in the hydropower station, there are hydropower stations that enter water mouth. Enter water mouth baseplate height 108 meters. Pressure input water pipeline for carry person who in charge of, interior diameter 12.40, adopt the armored concrete to receive the strength structure. Make and let out flow of 102500 cubic meters per second the most largely in the dam site while checking the flood.2. power stationsThe power stations adopt the type after the dam to assign the scheme, consist of two groups of factory buildings on left, right and underground factory building altogether. Install 32 sets of hydroelectric generating set together, 14 factory buildings of left bank among them, 12 factory buildings of right bank, 6 underground factory buildings. The hydraulic turbine, in order to mix the flowing type, the specified capacity of the unit of the unit is 700,000 kilowatts.3. open up to navigation buildingThe open up to navigation buildings include permanent lock and ship lift (of the the technological public relations, the steel cable that plans to be replaced with spiral pole technology in the original plan promotes technology), lie in the left bank. Permanent lock double-line five continuous chain of locks. Single grades of floodgate room effective size for 280*34*5, can pass the 10,000 ton-class fleet. The promoting type for single track first grade vertically of the ship lift is designed, it is 120*18*3.5 meters to bear the effective size of design of railway carriage or compartment of ship, can pass a combination vessel of 3000 tons once. Total weight is 11800 tons to bear the design of railway carriage or compartment of ship when operating, it is 6000 newtons to always promote strength.Three.The major project amount and arranges in time limit The subject building of the project and major project amount of the waterconservancy diversion project are: Excavate 102,830,000 cubic meters in cubic metre of earth and stone, fill out and build 31,980,000 cubic meters in cubic metre of earth and stone, concrete builds 27,940,000 cubic meters, 463,000 tons of reinforcing bars, make and fit 32 with hydroelectric generating set. All project construction tasks were divided into three stages and finished, all time limit was 17 years. The first stage (1993-1997 year) is preparation of construction and the first stage of the project, it takes 5 years to construct, regard realizing damming in the great river as the sign. The second stage (1998-2003 year) is the second stage, it takes 6 years to construct, lock as initial conservation storage of the reservoir, the first batch of aircrews generate electricity and is open up to navigation with the permanent lock as. The third stage (2004-2009 year) is the third stage of the project, it takes 6 years to construct, regard realizing the sign all aircrews generate electricity and finish building with all of multi-purpose project as. One, two project finish as scheduled already, the third stage of the project in inside the plan to construct too, ship lift tackle key problems of not going on intensely.Four. Enormous benefit of the Three Gorges Projects The Three Gorges Projects is the greatest water control project in China ,also in the world , it is the key project in controlling and developing the Changjiang River. The normal water storage level of the Three Gorges Projects reservoir is 175 meters, installed capacity is 39,300 million cubic meters; The total length of the reservoir is more than 600 kilometers, width is 1.1 kilometers on average; The area of the reservoir is 1084 sq. km.. It has enormous comprehensive benefits such as preventing flood, generating electricity, shipping,etc..1. prevent floodPrimary goal of building the Three Gorges Projects is to prevent flood . The key water control project in Sanxia is the key project that the midstream and downstream of the Changjiang River prevent flood in the system. Regulated and stored by the reservoir of Sanxia, form the capacity of reservoir in the upper reaches as river type reservoir of 39,300 million cubic meters, can regulate storage capacity and reach 22,150 million cubic meters, can intercept the flood came above of Yichang effectively, cut down flood crest flow greatly, make Jingjiang section prevent floodstandard meet, improve from at present a about over ten years to once-in-a-hundred-year. Meet millennium first special great flood that meet, can cooperate with Jingjiang flood diversion partition application of flood storage project, the crushing calamity of preventing the occurrence of both sides of section of Jingjiang and bursting in the main dike, lighten midstream and downstream losing and flood threat to Wuhan of big flood, and can create conditions for administration of Dongting Hu district.2. generates electricityThe most direct economic benefits of the Three Gorges Projects is to generate electricity . Equilibrate the contradiction that contemporary China develops economic and serious energy shortage at a high speed, the hydroelectric resources that a clean one can be regenerated are undoubtedly optimum choices. The total installed capacity of power station of Sanxia is 18,200,000 kilowatts, annual average generation is 84,680 million kilowatt hours. It will offer the reliable, cheap, clean regenerated energy for areas such as East China, Central China and South China of economic development, energy deficiency,etc.It play a great role in economic development and environmental pollution of reducing.Electric power resource that the Three Gorges Projects offers, if given a workforce of electricity generation by thermal power, mean building 10 more thermal power plants of 1,800,000 kilowatts, excavate more 50 million tons of raw coals every year on average. Besides environment of influencing of the waste residue, it will also discharge a large number of carbon dioxide which form the global greenhouse effects every year, cause the sulfur dioxide of acid rain, poisonous gas carbon monoxide and nitrogen oxide. At the same time, it will also produce a large amount of floating dust, dustfall,etc… Thermal power plant and abandon dreg field extensive occupation of land seize more land from East China, Central China area that have a large population and a few land just originally this. This not only makes China bear the pressure that greater environment brings in the future, cause unfavorable influence on the global environment too.3. shippingSanxia reservoir improve Yichang go to Chongqing channel of the ChangjiangRiver of 660 kilometers notably, the 10,000 ton-class fleet can go to the harbour of Chongqing directly. The channel can rise to 50 million tons from about 10 million tons at present through ability in one-way year, transporting the cost can be reduced by 35-37%. Unless until reservoir regulate, Yichang low water flows minimum seasons downstream,whose name is can since at present 3000 cubic meters /second improve until 5000 cubic meters per above second, the shipping condition get greater improvement too to enable the Changjiang River in low water season of midstream and downstream.Five. The questions in building the Three Gorges Projects1. silt issuethe Changjiang River Yichang Duan Nian amount of sand failed 530 million tons, silt the reservoir of Sanxia up. The reservoir blocks water level is 175 meters high, installed capacity is 39,300 million m3 normally,its die water level is 145 meters, the minimum capacity of a reservoir is 17,200 million m3, storage capacity 22,100 million m3, the conservation storage regulates the capacity of reservoir 16,500 million m3. The operation scheme of the reservoir is: Limit height is 145 meters of water level, in flood season, meet flood adjust big under 56700 m3 per second, and power station smooth to let out through deep hole over 3 years, can reduce the sand of the reservoir to deposit. Great flood comes, the reservoir is adjusted bigly, still put and let out 56700 m3per second; Deposit towards the reservoir after the flood. The reservoir begins conservation storage, between about two months and normal water storage level 175 meters high in September. The water level of the storehouse is dropped to 155 meters high before the flood next year, utilize conservation storage to generate electricity. In 155 meters water level, can keep the river shipping of Sichuan. By flood season, the water level was dropped to 145 meters water level again, because the flow was large at that time, could keep the river shipping of Sichuan. This is a reservoir operation scheme of innovation.2. question that the slope comes down by the bank of reservoir areaThe question that the slope comes down is through detailed geological survey by 2 reservoir area banks, there is several to come down potentially on water bank of Kuku of Sanxia, the big one can be up to millions of m3. But closest to dam sitepotential landslide, too far on 26 kilometers, such as happen, come down, shock wave that evoke get dam disappear, reduce 2-3 meters to to be high, it is safe not to influence the dam. In addition, if the slippery wave happens in the bank of the storehouse, because the reservoir is wide and deep, will not influence shipping.3. engineering question of the pivotThe pivot of Three Gorges is 185 meters high concrete gravity dam pivots and 18,200,000kW, the project amount is large, but all regular projects after all, our country has more experience. The stability problem of some foundation can meet the safe requirement through dealing with. 700,000kW hydroelectric generating set, imported from foreign countries in the first batch, was made by oneself at home later. The more complicated one is lock of five grades of Line two, deep-cut in the rock bank, slope reaches 170 meters at the supreme side, the underpart floodgate room vertical 60 meters, high rock slope stability worries about. But the meticulous research of engineer and constructors is designed, blown up and the anchor is firm and excavating, the rock slope is steady in a long-term. There is ship lift of 3000t passenger steamer, it is the biggest in the world, in course of designing and studying, and repair the test and use the ship lift first.4.ecological environment problemThe respect useful to ecological environment of the Three Gorges Projects is: Prevent and cure downstream land and cities and towns to flood, reduce the air pollution of electricity generation by thermal power, improve some climate, the reservoir can breed fish etc.. The respect disadvantageous to ecology is: Flood more than 300,000 mu of cultivated land, ground of fruit is more than 200,000 mu, immigrants reach the highland by the storehouse, will destroy the ecological environment, the still water weakens the sewage self-purification ability, worsen water quality, influence reproduction of the wild animal,etc. in the reservoir. So is both advantageous and disadvantageous, do not hinder building the Three Gorges Projects. Should reduce being unfavorable to minimum extent, it is mainly that reservoir immigrants want to plant trees and grass, build the terraced fields, ecological environment protection, does not require the self-sufficiency of grain. Accomplish these, want making a great effort and fund. Control blowdown such as Chongqing,Fuling, Wan County, carry on sewage disposal, protect the water quality of the reservoir, protect the wild animal, set up the protection zone. Although ecological environment protection is difficult, must solve and can solve. As for the scenery of Sanxia, because the high near kilometer of rock bank, and Sanxia dam is only in fact higher than the river surface 110 meters. The scenery basically remains unchanged, the high gorge produces Pinghu, increase even more beautifully.Six. Immigrant's question in the reservoir areaThe reservoir of Sanxia will flood 632 sq. km. of land area, will involve Chongqing, 20 county (market) of Hubei. The reservoir of Sanxia floods and involves 2 cities, 11 county towns, 116 market towns; Flood or flood 1599 of industrial and mining enterprises that influence, reservoir flood line there are 24,500 hectares of cultivated land in all; Flood 824.25 kilometers of highways, 92,200 kilowatts of power stations; The area of house of flooding area is 34,596,000 square meters, total population of living in the flooding area is 844,100 people (agricultural population 361,500 people among them). Consider population growth and other factors of moving etc. two times during construction, the total population of trends of reservoir immigration allocation of Sanxia will be up to 1,130,000 people. The task is arduous, but must find a room for good immigrants, make its life improve to some extent, help immigrants to create the working condition, live plainly and struggle hard through 20 years, grow rich. Most immigrants retreat to the highland, it is nonlocal that some immigrants get. The reservoir of Sanxia will flood 632 sq. km. of land area, will involve Chongqing, 20 county (market) of Hubei. The reservoir of Sanxia floods and involves 2 cities, 11 county towns, 116 market towns; Flood or flood 1599 of industrial and mining enterprises that influence, reservoir flood line own cultivated land (suck the ground of mandarin orange) 24,500 hectares in common; Flood 824.25 kilometers of highways, 92,200 kilowatts of power stations; The area of house of flooding area is 34,596,000 square meters, The total population of living in the flooding area is 844,100 people (agricultural population 361,500 people among them). Consider population growth and other factors of moving etc. two times during construction, the total population of trends of reservoir immigration allocation of Sanxia will be up to 1,130,000 people.1.exploration and opening of the immigrants in SanxiaThe exploration of an immigrant in Sanxia and open country are in the engineering construction of Sanxia, implement immigrant's policy of the exploration, relevant people's governments organize and lead immigrants to arrange work, use immigrant's funds in a unified manner, exploit natural resources rationally, based on agriculture, the agriculture,industry and commerce combine, through many channel, many industries, multi-form, many method find a room for immigrants properly, immigrants' living standard reach or exceed originally and competently, and create the condition for long-term economic development and improvement of immigrant's living standard of reservoir area of Three Gorges. Immigrant's policy of the exploration, is a great reform of the reservoir immigrants of our country. Policy this, and reservoir area of Three Gorges immigrant put forward at the foundation of pilot project eight year in experience and lessons that immigrant work since new China set up of summarizing. At the beginning of reservoir immigrants in Sanxia, carry out exploration immigrants' principles and policies, insist the country supports, the policy is favourable, each side supports, principle of relying on one's own efforts, appeared by the government, develop local resources in a planned way, expand the capacity of placing, help, offer service of forming a complete set, wide to open up, produce the life way, make it reach " take out offing, goal that so steady as to live, can get rich progressively ". Meanwhile, the country approves reservoir area of Three Gorges as " the open economic region of Sanxia ", enjoy some special policies opening to the outside world in the coastal area, call the immigrants in Sanxia of the developed coordinated cooperation of province and city, immigrant's enterprises and relevant The factor of production has been pushed to the broader large market. The governments at all levels of reservoir area of Three Gorges have issued some development coordinated cooperation, favourable measure inviting outside investment too. Reservoir area immigrant demonstrate with open to urge, develop, in order to develop, urge benign situation that place.2. reorganization and expansion of the immigrants in SanxiaThe reorganization of immigrants in Sanxia and the expansion immigrants in Sanxia are that one involve undertaking that the society of reservoir area reconstruct,resources are recombinated, the recombinating is one of the prominent characteristics of the immigrants in Sanxia, move the fundamental difference duplicated with traditional simple compensation immigrants, former state too. Implement immigrant's policy of the exploration, must demand to combine immigrants to move, reconfigure the factor of production, thus improve the disposition efficiency of resources, form new productivity. Expand while being what is called, expansion of scale, improvement of structure even more, function strengthen improvement of quality. Look with the view of development economics and implement the course of exploration immigrants, it is the course of economic expansion of reservoir area. Exploration immigrants begin from expanding, and ending at realizing expanding, the course that the whole immigrant move and rebuild one's home is running through economic expansion, full of to the yearning that expands in the future. Certainly, in actual operation, should set out from immigrant's reality to pay attention to all, insist reason is expanded.Seven. Investment and benefit questionInvests 90,090 million yuan (1993 price) in investment and the Three Gorges Projects static behavior of benefit question, invests more than about 200 billion yuan dynamically while finishing in project. The investment source of the Three Gorges Projects is as follows, state loan, state-run hydropower station each of price of electricity raise the price 0.4-0.7 fen, power station electric rate income of Ge Zhou Ba, the electric rate income after the power station of Sanxia generates electricity wait for, the country has this financial resources to guarantee to invest in putting in place. About benefit, it is estimated it in ten years after the Three Gorges Projects is built up, total project investment principal and interest, unless including project fee and fee for immigration, can have repaid with electric rate income,it prevent flood, shipping,etc. share make the investment. And the Three Gorges Projects prevent flood, generate electricity, shipping,etc. benefit long-term, and enormous social benefit. Therefore, benefit of the Three Gorges Projects is very great, there is increase slightly to even make the investment, it is very rational too to repay service life to slightly lengthen.三峡水利枢纽工程一、坝址及基本枢纽布置三峡工程大坝坝址选定在宜昌市三斗坪，在已建成的葛洲坝水利枢纽上游约40km处。

中英文对照外文翻译(文档含英文原文和中文翻译)原文:Strength of Concrete in Slabs, Investigates along Directionof ConcretingABSTRACTIn theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor s lab’s or a beam’s strength is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strengthalong the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations [1-3].Keywords: Concrete; Compressive Strength of Concrete; Non-Destructive1. IntroductionIn a building structure there are components which are expected to have special properties but not necessarily in the whole cross section. Components under bending, such as beams and floor slabs are generally compressed in their upper zone and the concrete’s compressive strength is vital mainly in this zone. The components are usually moulded in the same position in which they later remain in service, i.e. with their upper zone under compression. Concrete in the upper zone is expected to be slightly weaker than in the lower zone, but it is unclear how much weaker [4,5]. Also flooring slabs in production halls are most exposed to abrasion and impact loads in their upper zone which is not their strongest part. It is known from practice that industrial floors belong to the most often damaged building components.When reinforced concrete beams or floor slabs are to be tested they can be accessed only from their undersides and so only the bottom parts are tested and on this basis conclusions are drawn about the strength of the concrete in the whole cross section, including in the compressed upper zone. Thus a question arises: how large are the errors committed inthis kind of investigations?In order to answer the above and other questions, tests of the strength of concrete in various structural components, especially in horizontally concreted slabs, were carried out. The variation of strength along the thickness of the components was analyzed.2. Research SignificanceThe research results presented in the paper show that the compressive strength of concrete in horizontally formed structural elements varies along their thickness. In the top zone the strength is by 25% - 30% lower than the strength in the middle zone, and it can be by as much as 100% lower than the strength in the bottom zone. The observations are based on the results of nondestructive tests carried out on drill cores taken from the structure, and verified by a destructive method. It is interesting to note that despite the great advances in concrete technology, the variation in compressive strength along the thickness of structural elements is characteristic of both old (over 60 years old) concretes and contemporary ordinary concretes.3. Test MethodologyBefore Concrete strength was tested by the ultrasonic method using exponential heads with a point contact with concrete. The detailed specifications of the heads can be found in [2,3]. The heads’ frequency was 40 and 100 kHz and the diameter of their concentrators amounted to 1 mm.In order to determine the real strength distributions in the existing structures, cylindrical cores 80 mm or 114 mm diameter (Figure 2) were drilled from them in the direction of concreting. Then specimens with their height equal to their diameter were cut out of the cores.Ultrasonic measurements were performed on the cores according to the scheme shown in Figure 3. Ultrasonic pulses (pings) were passed through in two perpendicular directions I and II in planes spaced every 10 mm. In this way one could determine how ping velocity varied along the core’s height, i.e. along the thickness of the tested component.In both test directions ping pass times were determined and velocities CL were calculated. The velocities from the two directions in a tested measurement plane were averaged.Subsequently, specimens with their height equal to their diameter of 80 mm were cut out of the cores. Aver-age ultrasonic pulse velocity CL for the specimen’s central zone was correlated with fatigue strength fc determined by destructive tests carried out in a strength tester.For the different concretes different correlation curves with a linear, exponential orpower equation were obtained. Exemplary correlation curve equations are given below:Lc c L c C f L f C f 38.1exp 0951.01.003.56705.232621.4=⋅=-⨯=where: fc —the compressive strength of concrete MPa,CL —ping velocity km/s.The determined correlation curve was used to calculate the strength of concrete in each tested core cross section and the results are presented in the form of graphs illustrating concrete strength distribution along the thickness of the tested component.4. Investigation of Concrete in Industrial FloorsAfter Floor in sugar factory’s raw materials storage hall Concrete in an industrial floor must have particularly good characteristics in the top layer. Since it was to be loaded with warehouse trucks and stored sugar beets and frequently washed the investigated concretefloor (built in 1944) was designed as consisting of a 150 mm thick underlay and a 50 mm thick surface layer and made of concrete with a strength of 20 MPa (concrete A).As part of the investigations eight cores, each 80 mm in diameter, were drilled from the floor. The investigations showed significant departures from the design. The concrete subfloor’s thickness varied from 40 to 150 mm. The surface layer was not made of concrete, but of cement mortar with sand used as the aggregate. Also the thickness of this layer was uneven, varying from 40 to 122mm. After the ultrasonic tests specimens with their height equal to their diameter of 80 mm were cut out of the cores. Two scaling curves: one for the surface layer and the other for the bottom concrete layer were determined.A characteristic concrete compressive strength distribution along the floor’s thickness is shown in Figure 4.Strength in the upper zone is much lower than in the lower zone: ranging from 4.7 to 9.8 MPa for the mortar and from 13.9 to 29.0 MPa for the concrete layer. The very low strength of the upper layer of mortar is the result of strong porosity caused by air bubbles escaping upwards during the vibration of co ncrete. Figure 5 shows the specimen’s porous top surface.Floor in warehouse hall with forklift truck transport The floor was built in 1998. Cellular concrete was used as for the underlay and the 150 mm thick surface layer was made of ordinary concrete with fibre (steel wires) reinforcement (concrete B). Cores 80 mm high and 80 mm in diameter were drilled from the surface layer. Ultrasonic measurements and destructive tests were performed as described above. Also the test results were handled in a similar way. An exemplary strength distribution along the floor’s thickness is shown in Figure 6.5. ConclusionsTests of ordinary concretes show unexpectedly greatly reduced strength in the upper zone of horizontally moulded structural components. This is to a large degree due to thevibration of concrete as a result of which coarse aggregate displaces downwards making the lower layers more compact while air moves upwards aerating the upper layers and thereby increasing their porosity. The increase in the concre te’s porosity results in a large drop in its compressive strength. Thanks to the use of the ultrasonic method and probes with exponential concentrators it could be demonstrated how the compressive strength of ordinary concrete is distributed along the thickness of structural components in building structures. It became apparent that the reduction in compressive strength in the compressed zone of structural components under bending and in industrial concrete floors can be very large (amounting to as much as 50% of the strength of the slab’s lower zone). Therefore this phenomenon should be taken into account at the stage of calculating slabs, reinforced concrete beams and industrial floors [6].The results of the presented investigations apply to ordinary concretes (OC) which are increasingly supplanted by self-compacting concretes (SCC) and high-performance concretes (HPC). Since no intensive vibration is required to mould structures from such concretes one can expect that they are much more homogenous along their thickness [7]. This will be known once the ongoing experimental research is completed.Bohdan StawiskiStrength of Concrete in Slabs, Investigates along Direction of Concreting[D]Institute of Building Engineering, Wroclaw University of Technology Wybrzeze Wyspianskiego, Wroclaw, PolandReceived October 15, 2011; revised November 21, 2011; accepted November 30, 2011译文:混凝土强度与混凝土浇筑方向关系的研究摘要从理论上看，假设混凝土复合材料是各项同性的从宏观尺度上讲。

The roller-compacted concrete gravity dam(1)The synopsis of the roller—compacted concrete gravity damThe concrete gravity dam shares with the embankment the central attributes of simplicity of concept and adaptability, but conventional mass concrete construction rates, unlike those for embankment construction ,remain essentially as they were m the 1950s. the volume instability of mass concrete due to thermal effects imposes severe limitations on the size and rate of concret pour, causing delay and disruption through the need to provide contraction joints and similar design features. Progressive reductions in cement content and partial replacement of cement with PFA have served only to contain the problem. Mass concrete construction remains a semi-continuous and labour- intensive operation of low overall productivity and efficiency.In some circumstances the technical merits of the gravity dam and the embankment may be evenly balanced. selection resting on estimated construction cost. Economic advantage will almost invariably favour the embankment. particularly if constructed in compacted rockfill. In some instances ,however, factors such as locating a spillway of sufficient capacity etc. may indicate the concrete gravity dam as being a preferable design solution. provided that the cost differential lies within acceptable limits.Despite advances in embankment dam engineering, therefore, there remains a strong incentive to develop a cheaper concrete gravity dam.The problem of optimizing concrete dam construction and reducing costs can be approached in several ways. In the absence of progress towards an ideal cement and a dimensionally stable concrete the most promising lines of approach may be classified as follows:1. A reappraisal of design criteria, particularly with regard to accepting modest tensile stresses;2.The development of improved mass concretes through the use ofadmixtures to enhance tensile strength and to modify stress-strain response. and/or the use of modified cements with reduced thermal activity;3. The development of rapid continuous construction techniques based on the use of special concrete.Neither of the first two approaches is capable of offering other than a token reduction in cost. the third option offers the greatest potential through financial benefits associated with a shortening of construction period by up to 35% combined with a lower-cost variant of concrete.The concept of dam construction using roller-compacted concrete (RCC), first developed in the 1970s, is based primarily on approach 3.Several variants of RCC have now been developed and offer the prospect of significantly faster and cheaper construction. particularly for large.gravity dams.(2) developments in roller-compacted concrete dam constructionThe RCC dam has developed rapidly since construction of the earliest examples in the early 1980s. and in excess of 200 large dams had been completed in RCC by 2000.the majority of RCC dams have Been gravity structures, but the RCC technique has been extended to a number of archgravity and thick arch dams As confidence has grown RCC has been used for progressively larger dams, and RCC is being employed for the major part of the 7. 6 x 106m3 volume and 217m high longtan gravity dam, under construction in China. In a number of recent instances the RCC gravity dam option has been selected in preference to initial proposals for the construction of a rockfill embankment.The early RCC dam were noted for problems associated with relatively high seepage and leakage through the more permeable RCC. and for a degree of uncontrolled cracking (Hollingworth and Geringer. 1992). A rela -tively low interlayer bond strength also prompted some concern. particularly in the context of seismic loading .the philosophy of RCC dam design has inconsequence evolved. with emphasis being placed on optimizing design anddetailing to construction in RCC rather than using RCC to construct a con- ventional gravity dam .This trend has led to the common provision ofan”impermeable” upstream element or barrier, e. g. by a slip-formed facing (Fig 3.22 and also New Victoria dam.Australia (Ward and Mann ,1992)).An alternative is the use of a PVC or similar synthetic membrane placed against or Just downstream of a high-quality concrete upstream face In the case of the 68m high Concepcion gravity dam, Honduras. a 3 .2mm PVC geomembrane backed by a supporting geotextile drainage layer was applied to the upstream face of the RCC (Giovagnoli, schrader and Ercoli ,1992). Recent practice has also moved towards control of cracking by sawn transverse Joints, or by the cutting of a regular series of slots to act as crack Inducers.The very considerable cost savings attaching to RCC construction are dependent upon plant and RCC mix optimization ,and hence continuity of the RCC placing operation. This in turn requires that design features which interfere continuous unobstructed end-to-end placing of the RCC, egg. galleries. internal pipework, etc.. Must be kept to the minimum and simplified. Experiments with retrospectively excavating gallerries by trenching and by driving a heading in the placed RCC fill at Riou, France. have proved successful (goubet and guerinet, 1992).Vertical rates of raising of 2.0-2.5 m week-1 are attainable for RDLC and high-paste RCCs compared with 1. 0-1.5m week-1 for RCD con- struction As one example, the Conception dam, Honduras, referred to earlier was raised in seven months. A lean RCC mix (cement content 80-95kgm-3) was employedfor the 290 x 103m3 of RCC fill, and a continuous mixing plant was used In conjunction with a high-speed belt conveyor system. Placing rates of up to 4000m3 days-1 were ultimately attained (Gio vagnoli, Schraderand Ercoli, 1992).The employment of RCC fill has also been extended to the upgrading of existing dams, e.g. by placing a downstream shoulder where stability is deficient (Section 3. 2. 9) .RCC has also Been applied to general remedialworks and to raising or rebuilding older dams. the benefits of RCC con- struction have also been appropriate. in special circumstances. to the con- struction of smaller dams, e.g. Holbeam wood and New Mills in the UK (Iffla, Millmore and Dunstan. 1992).ICOLD Bulletin 75 (ICOLD,1989) provides a comprehensive over- view of the use of RCC for dam construction. Recent US developments are discussed in Hansen (1994). Design options with respect to upstream face construction have Been reviewed in some detail by Schrader (1993).Construction in RCC is recognized as providing the way forward in concrete dam engineering .An extensive review of current issues in RCC dam design and construction is presented within Li (1998) .Major issues discussed include the need. or otherwise, for a conventional concrete upstream face, and the question of resistance to high seismic Ioading.where dynamic tensile strength of the interlayer bond between successive layers of RCC will be critical.The recently completed 95m high RCC gravity dam. at P1atanovryssi, Greece, located in a seismic zone is described in Stefanakos and Dunston (1999). the design peak ground acceleration corresponding to the MCE at Platanovryssi was determined as 0.385g, equating to a maximum dynamic crack inducers vibrated into the RCC. the “joints” were subsequently sealed by a 600mm wide external waterstop bonded to the face. Seepage through the dam body diminished to a satisfactory 10-12l/s over the first 12 months' operational service.The first use of RCC in Turkey, for the 124m high by 290m long Cine gravity dam (originally planned as a rockfill embankment with a clay core) is presented in Ozdogan (1999). the low-paste RCC used for cine has a cement content of 70kg/m3. with 90kg/m3 of PFA and 88 l/m3 of water. Target 180 day compressive strength was specified as 24MN/m2.碾压混凝土重力坝(1)碾压混凝土坝的简介混凝土重力坝和土石坝样具有概念简单和适用性强的特性，但常规大体积混凝土施工速度不象土石坝施工提高那样快，还维持在1950年代的水平。

土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。

外文文献：hydraulicturbines and hydro-electric powerAbstractPower may be developed from water by three fundamental processes : by action of its weight, of its pressure, or of its velocity, or by a combination of any or all three. In modern practice the Pelton or impulse wheel is the only type which obtains power by a single process the action of one or more high-velocity jets. This type of wheel is usually found in high-head developments. Faraday had shown that when a coil is rotated in a magnetic field electricity is generated. Thus, in order to produce electrical energy, it is necessary that we should produce mechanical energy, which can be used to rotate the ‘coil’. The mechanical energy is produced by running a prime mover (known as turbine ) by the energy of fuels or flowing water. This mechanical power is converted into electrical power by electric generator which is directly coupled to the shaft of turbine and is thus run by turbine. The electrical power, which is consequently obtained at the terminals of the generator, is then transited to the area where it is to be used for doing work.he plant or machinery which is required to produce electricity (i.e. prime mover +electric generator) is collectively known as power plant. The building, in which the entire machinery along with other auxiliary units is installed, is known as power house.Keywords hydraulic turbines hydro-electric power classification of hydel plants head schemeThere has been practically no increase in the efficiency of hydraulic turbines since about 1925, when maximum efficiencies reached 93% or more. As far as maximum efficiency is concerned, the hydraulic turbine has about reached the practicable limit of development. Nevertheless, in recent years, there has been a rapid and marked increase in the physical size and horsepower capacity of individual units.In addition, there has been considerable research into the cause and prevention of cavitation, which allows the advantages of higher specific speeds to be obtained at higher heads than formerly were considered advisable. The net effect of this progress with larger units, higher specific speed, and simplification and improvements in design has been to retain for the hydraulic turbine the important place which it haslong held at one of the most important prime movers.1. types of hydraulic turbinesHydraulic turbines may be grouped in two general classes: the impulse type which utilizes the kinetic energy of a high-velocity jet which acts upon only a small part of the circumference at any instant, and the reaction type which develops power from the combined action of pressure and velocity of the water that completely fills the runner and water passages. The reaction group is divided into two general types: the Francis, sometimes called the reaction type, and the propeller type. The propeller class is also further subdivided into the fixed-blade propeller type, and the adjustable-blade type of which the Kaplan is representative.1.1 impulse wheelsWith the impulse wheel the potential energy of the water in the penstock is transformed into kinetic energy in a jet issuing from the orifice of a nozzle. This jet discharge freely into the atmosphere inside the wheel housing and strikes against the bowl-shaped buckets of the runner. At each revolution the bucket enters, passes through, and passes out of the jet, during which time it receives the full impact force of the jet. This produces a rapid hammer blow upon the bucket. At the same time the bucket is subjected to the centrifugal force tending to separate the bucket from its disk. On account of the stresses so produced and also the scouring effects of the water flowing over the working surface of the bowl, material of high quality of resistance against hydraulic wear and fatigue is required. Only for very low heads can cast iron be employed. Bronze and annealed cast steel are normally used.1.2 Francis runnersWith the Francis type the water enters from a casing or flume with a relatively low velocity, passes through guide vanes or gates located around the circumstance, and flows through the runner, from which it discharges into a draft tube sealed below the tail-water level. All the runner passages are completely filled with water, which acts upon the whole circumference of the runner. Only a portion of the power is derived from the dynamic action due to the velocity of the water, a large part of the power being obtained from the difference in pressure acting on the front and back of the runner buckets. The draft tube allows maximum utilization of the available head, both because of the suction created below the runner by the vertical column of water and because the outlet of he draft tube is larger than the throat just below the runner, thus utilizing a part of the kinetic energy of the water leaving the runner blades.1.3 propeller runnersnherently suitable for low-head developments, the propeller-type unit has effected marked economics within the range of head to which it is adapted. The higher speed of this type of turbine results in a lower-cost generator and somewhat smaller powerhouse substructure and superstructure. Propeller-type runners for low heads andsmall outputs are sometimes constructed of cast iron. For heads above 20 ft, they are made of cast steel, a much more reliable material. Large-diameter propellers may have individual blades fastened to the hub.1.4 adjustable-blade runnersThe adjustable-blade propeller type is a development from the fixed-blade propeller wheel. One of the best-known units of this type is the Kaplan unit, in which the blades may be rotated to the most efficient angle by a hydraulic servomotor. A cam on the governor is used to cause the blade angle to change with the gate position so that high efficiency is always obtained at almost any percentage of full load.By reason of its high efficiency at all gate openings, the adjustable-blade propeller-type unit is particularly applicable to low-head developments where conditions are such that the units must be operated at varying load and varying head. Capital cost and maintenance for such units are necessarily higher than for fixed-blade propeller-type units operated at the point of maximum efficiency.2. thermal and hydropowerAs stated earlier, the turbine blades can be made to run by the energy of fuels or flowing water. When fuel is used to produce steam for running the steam turbine, then the power generated is known as thermal power. The fuel which is to be used for generating steam may either be an ordinary fuel such as coal, fuel oil, etc., or atomic fuel or nuclear fuel. Coal is simply burnt to produce steam from water and is the simplest and oldest type of fuel. Diesel oil, etc. may also be used as fuels for producing steam. Atomic fuels such as uranium or thorium may also be used to produce steam. When conventional type of fuels such s coal, oil, etc. (called fossils ) is used to produce steam for running the turbines, the power house is generally called an Ordinary thermal power station or Thermal power station. But when atomic fuel is used to produce steam, the power station, which is essentially a thermal power station, is called an atomic power station or nuclear power station. In an ordinary thermal power station, steam is produced in a water boiler, while in the atomic power station; the boiler is replaced y a nuclear reactor and steam generator for raising steam. The electric power generated in both these cases is known as thermal power and the scheme is called thermal power scheme.But, when the energy of the flowing water is used to run the turbines, then the electricity generated is called hydroelectric power. This scheme is known as hydro scheme, and the power house is known as hydel power station or hydroelectric power station. In a hydro scheme, a certain quantity of water at a certain potential head is essentially made to flow through the turbines. The head causing flow runs the turbine blades, and thus producing electricity from the generator coupled to turbine. In this chapter, we are concerned with hydel scheme only.3.classification of hydel plantsHydro-plants may be classified on the basis of hydraulic characteristics as follow: ①run-off river plants .②storage plants.③pumped storage plants.④tidal plants. they are described below.(1)Run-off river plants.These plants are those which utilize the minimum flow in a river having no appreciable pondage on its upstream side. A weir or a barrage is sometimes constructed across a river simply to raise and maintain the water level at a pre-determined level within narrow limits of fluctuations, either solely for the power plants or for some other purpose where the power plant may be incidental. Such a scheme is essentially a low head scheme and may be suitable only on a perennial river having sufficient dry weather flow of such a magnitude as to make the development worthwhile.Run-off river plants generally have a very limited storage capacity, and can use water only when it comes. This small storage capacity is provided for meeting the hourly fluctuations of load. When the available discharge at site is more than the demand (during off-peak hours ) the excess water is temporarily stored in the pond on the upstream side of the barrage, which is then utilized during the peak hours.he various examples of run-off the river pant are: Ganguwal and Kolta power houses located on Nangal Hydel Channel, Mohammad Pur and Pathri power houses on Ganga Canal and Sarda power house on Sarda Canal.The various stations constructed on irrigation channels at the sites of falls, also fall under this category of plants.(2) Storage plantsA storage plant is essentially having an upstream storage reservoir of sufficient size so as to permit, sufficient carryover storage from the monsoon season to the dry summer season, and thus to develop a firm flow substantially more than minimum natural flow. In this scheme, a dam is constructed across the river and the power house may be located at the foot of the dam such as in Bhakra, Hirakud, Rihand projects etc. the power house may sometimes be located much away from the dam (on the downstream side). In such a case, the power house is located at the end of tunnels which carry water from the reservoir. The tunnels are connected to the power house machines by means of pressure pen-stocks which may either be underground (as in Mainthon and Koyna projects) or may be kept exposed (as in Kundah project).When the power house is located near the dam, as is generally done in the low head installations ; it is known as concentrated fall hydroelectric development. But when the water is carried to the power house at a considerable distance from the dam through a canal, tunnel, or pen-stock; it is known as a divided fall development.(3) Pumped storage plants.A pumped storage plant generates power during peak hours, but during theoff-peak hours, water is pumped back from the tail water pool to the headwater pool for future use. The pumps are run by some secondary power from some other plant in the system. The plant is thus primarily meant for assisting an existing thermal plant or some other hydel plant.During peak hours, the water flows from the reservoir to the turbine and electricity is generated. During off-peak hours, the excess power is available from some other plant, and is utilized for pumping water from the tail pool to the head pool, this minor plant thus supplements the power of another major plant. In such a scheme, the same water is utilized again and again and no water is wasted.For heads varying between 15m to 90m, reservoir pump turbines have been devised, which can function both as a turbine as well as a pump. Such reversible turbines can work at relatively high efficiencies and can help in reducing the cost of such a plant. Similarly, the same electrical machine can be used both as a generator as well as a motor by reversing the poles. The provision of such a scheme helps considerably in improving the load factor of the power system.(4) Tidal plantsTidal plants for generation of electric power are the recent and modern advancements, and essentially work on the principle that there is a rise in seawater during high tide period and a fall during the low ebb period. The water rises and falls twice a day; each fall cycle occupying about 12 hours and 25 minutes. The advantage of this rise and fall of water is taken in a tidal plant. In other words, the tidal range, i.e. the difference between high and low tide levels is utilized to generate power. This is accomplished by constructing a basin separated from the ocean by a partition wall and installing turbines in opening through this wall.Water passes from the ocean to the basin during high tides, and thus running the turbines and generating electric power. During low tide，the water from the basin runs back to ocean, which can also be utilized to generate electric power, provided special turbines which can generate power for either direction of flow are installed. Such plants are useful at places where tidal range is high. Rance power station in France is an example of this type of power station. The tidal range at this place is of the order of 11 meters. This power house contains 9 units of 38,000 kW.4.Hydro-plants or hydroelectric schemes may be classified on the basis of operating head on turbines as follows: ①low head scheme (head<15m),②medium head scheme (head varies between 15m to 60 m) ,③high head scheme (head>60m). They are described below:(1) Low head scheme.A low head scheme is one which uses water head of less than 15 meters or so. A run off river plant is essentially a low head scheme, a weir or a barrage is constructed to raise the water level, and the power house is constructed either in continuation withthe barrage or at some distance downstream of the barrage, where water is taken to the power house through an intake canal.(2) Medium head schemeA medium head scheme is one which used water head varying between 15 to 60 meters or so. This scheme is thus essentially a dam reservoir scheme, although the dam height is mediocre. This scheme is having features somewhere between low had scheme and high head scheme.(3) High head scheme.A high head scheme is one which uses water head of more than 60m or so. A dam of sufficient height is, therefore, required to be constructed, so as to store water on the upstream side and to utilize this water throughout the year. High head schemes up to heights of 1,800 meters have been developed. The common examples of such a scheme are: Bhakra dam in (Punjab), Rihand dam in (U.P.), and Hoover dam in (U.S.A), etc.The naturally available high falls can also be developed for generating electric power. The common examples of such power developments are: Jog Falls in India, and Niagara Falls in U.S.A.水轮机和水力发电摘要水的能量可以通过三种基本方法来获得：利用水的重力作用、水的压力作用或水的流速作用，或者其中任意两种或全部三种作用的组合。

DamThe first dam for which there are reliable records was build or the Nile River sometime before 4000 . It was used to divert the Nile and provide a site for the ancient city of Memphis .The oldest dam still in use is the Almanza Dam in Spain, which was constructed in the sixteenth century. With the passage of time,materials and methods of construction have improved. Making possible the erection of such large dams as the Nurek Dam, which is being constructed in the . on the vaksh River near the border of Afghanistan. This dam will be 1017ft(333m) high, of earth and rock fill. The failure of a dam may cause serious loss of life and property; consequently, the design and maintenance of dams are commonly under government surveillance. In the United States over 30,000 dams are under the control of state authorities. The 1972 Federal Dams Safety Act (PL92-367)requires periodic inspections of dams by qualified experts. The failure of the Teton Dam in Idaho in June 1976 added to the concern for dam safety in the United States.1 Type of DamsDams are classified on the type and materials of construction, as gravity, arch, buttress ,and earth .The first three types are usually constructed of concrete. A gravity dam depends on its own weight for stability and it usually straight in plan although sometimes slightly curved.Arch dams transmit most of the horizontal thrust of the water behind them to the abutments by arch action and have thinner cross sections than comparable gravity dams. Arch dams can be used only in narrow canyons where the walls are capable of withstanding the thrust produced by the arch action. The simplest of the many types of buttress dams is the slab type, which consists of sloping flat slabs supported at intervals by buttresses. Earth dams are embankments of rock or earth with provision for controlling seepage by means of dam may be included in a single structure. Curved dams may combine both gravity and arch action to achieve stability. Long dams often have a concrete river section containing spillway and sluice gates and earth or rock-fill wing dams for the remainder of their length.The selection of the best type of dam for a given site is a problem in both engineering feasibility and cost. Feasibility is governed by topography, geology and climate. For example, because concrete spalls when subjected to alternate freezing and thawing, arch and buttress dams with thin concrete section are sometimes avoided in areas subject to extreme cold. The relative cost of the various types of dams depends mainly on the availability of construction materials near the site and the accessibility of transportation facilities. Dams are sometimes built in stages with the second or late stages constructed a decade or longer after the first stage.The height of a dam is defined as the difference in elevation between the roadway, or spillway crest, and the lowest part of the excavated foundation. However, figures quoted for heights of dams are often determined in other ways. Frequently the height is taken as the net height is taken as the net height above the old riverbed.on damsA dam must be relatively impervious to water and capable of resisting the forces acting on it. The most important of these forces are gravity (weight of dam) , hydrostatic pressure, uplift, ice pressure, and earthquake forces are transmitted to the foundation and abutments of the dam, which react against the dam with an equal and opposite force, the foundation reaction. The effect of hydrostatic forces caused by water flowing over the dam may require consideration in special cases.The weight of a dam is the product of its volume and the specific weight of the material. The line of action of dynamic force passes through the center of mass of the cross section. Hydrostatic force may act on both the upstream and downstream faces of the dam. The horizontal componentH of the hydrostatic force is the force or unit width of damhit is2/2HrhhWhere r is the specific weight of water and h is the depth of water .The line of action of this force is h/3 above the base of thedam .The vertical component of the hydrostatic force is equal to the weigh of water vertically above the face of the dam and passes through the center of gravity of this volume of water.Water under pressure inevitably finds its way between the dam And its foundation and creates uplift pressures. The magnitude of the uplift force depends on the character of the foundation and the construction methods. It is often assumed that the uplift pressure varies linearly from full hydrostatic pressure at the upstream face (heel)to full tail-water pressure at the downstream face (toe).For this assumption the uplift force U isU=r(h1+h2)t/2Where t is the base thickness of the dam and h1and h2 are the water depths at the heel and toe of the dam,respectively. The uplift force will act through the center of area of the pressure trapezoid.Actual measurements on dams indicate that the uplift force is much less than that given by Eq.(2)Various assumption have been made regarding the distribution of uplift of Reclamation sometimes assumes that the uplift pressure on gravity dams varies linearly from two-thirds of full uplift at the heel to zero at the toe. Drains are usually provided near the heel of the dam to permit the escape of seepage water and relieve uplift.译文：坝据可靠记载，世界上第一座坝是公元前4000年以前在尼罗河上修建的。

钢筋混凝土中英文资料翻译1 外文翻译1.1 Reinforced ConcretePlain concrete is formed from a hardened mixture of cement ,water ,fine aggregate, coarse aggregate (crushed stone or gravel),air, and often other admixtures. The plastic mix is placed and consolidated in the formwork, then cured to facilitate the acceleration of the chemical hydration reaction lf the cement/water mix, resulting in hardened concrete. The finished product has high compressive strength, and low resistance to tension, such that its tensile strength is approximately one tenth lf its compressive strength. Consequently, tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete element.It is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design. The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved. This is possible because concrete can easily be given any desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned, the finished product becomes strong, durable, and, in combination with the reinforcing bars, adaptable for use as main members of anystructural system.The techniques necessary for placing concrete depend on the type of member to be cast: that is, whether it is a column, a bean, a wall, a slab, a foundation. a mass columns, or an extension of previously placed and hardened concrete. For beams, columns, and walls, the forms should be well oiled after cleaning them, and the reinforcement should be cleared of rust and other harmful materials. In foundations, the earth should be compacted and thoroughly moistened to about 6 in. in depth to avoid absorption of the moisture present in the wet concrete. Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type, as the case requires, unless it is placed by pumping. It must be kept in mind, however, that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concrete.Hydration of the cement takes place in the presence of moisture at temperatures above 50°F. It is necessary to maintain such a condition in order that the chemical hydration reaction can take place. If drying is too rapid, surface cracking takes place. This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydration.It is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element, such as geometrical width, depth, area of reinforcement, steel strain, concrete strain, steel stress, and so on. Consequently, trial and adjustment is necessary in the choice of concrete sections, with assumptions based on conditions at site, availability of the constituent materials, particular demands of the owners, architectural and headroom requirements, the applicable codes, and environmental reinforced concrete is often a site-constructed composite, in contrast to the standard mill-fabricated beam and column sections in steel structures.A trial section has to be chosen for each critical location in a structural system. The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load. Since more than one trial is often necessary to arrive at the required section, the first design input step generates into a series of trial-and-adjustment analyses.The trial-and –adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design. Hence every design is an analysis once a trial section is chosen. The availability of handbooks, charts, and personal computers and programs supports this approach as a more efficient, compact, and speedy instructionalmethod compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design.1.2 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering, this is a field where there are real opportunities for the enthusiast. In 1935 most of the methods now in use for carrying and excavating earth with rubber-tyred equipment did not exist. Most earth was moved by narrow rail track, now relatively rare, and the main methods of excavation, with face shovel, backacter, or dragline or grab, though they are still widely used are only a few of the many current methods. To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines. Generally the only reliable up-to-date information on excavators, loaders and transport is obtainable from the makers.Earthworks or earthmoving means cutting into ground where its surface is too high ( cuts ), and dumping the earth in other places where the surface is too low ( fills). Toreduce earthwork costs, the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill. This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness. From the available maps ahd levels, the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork. On the site when further information becomes available he can make changes in jis sections and layout,but the drawing lffice work will not have been lost. It will have helped him to reach the best solution in the shortest time.The cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine. This is not always possible, but when it canbe done it is ideal, being both quick and cheap. Draglines, bulldozers and face shovels an do this. The largest radius is obtained with the dragline,and the largest tonnage of earth is moved by the bulldozer, though only over short distances.The disadvantages of the dragline are that it must dig below itself, it cannot dig with force into compacted material, it cannot dig on steep slopws, and its dumping and digging are not accurate.Face shovels are between bulldozers and draglines, having a larger radius of action than bulldozers but less than draglines. They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline.Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful, but its dumping radius is considerably less than that of the same escavator fitted with a face shovel.Rubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel. They can dig the material deeply ( but only below themselves ) to a fairly flat surface, carry it hundreds of meters if need be, then drop it and level it roughly during the dumping. For hard digging it is often found economical to keep a pusher tractor ( wheeled or tracked ) on the digging site, to push each scraper as it returns to dig. As soon as the scraper is full,the pusher tractor returns to the beginning of the dig to heop to help the nest scraper.Bowl scrapers are often extremely powerful machines;many makers build scrapers of 8 cubic meters struck capacity, which carry 10 m ³ heaped. The largest self-propelled scrapers are of 19 m ³ struck capacity ( 25 m ³ heaped )and they are driven by a tractor engine of 430 horse-powers.Dumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials. Dumpers have the earth container over the front axle on large rubber-tyred wheels, and the container tips forwards on most types, though in articulated dumpers the direction of tip can be widely varied. The smallest dumpers have a capacity of about 0.5 m ³, and the largest standard types are of about 4.5 m ³. Special types include the self-loading dumper of up to 4 m ³and the articulated type of about 0.5 m ³. The distinction between dumpers and dump trucks must be remembered .dumpers tip forwards and the driver sits behind the load. Dump trucks are heavy, strengthened tipping lorries, the driver travels in front lf the load and the load is dumped behind him, so they are sometimes called rear-dump trucks.1.3 Safety of StructuresThe principal scope of specifications is to provide general principles and computational methods in order to verify safety of structures. The “ safety factor ”, which according to modern trends is independent of the nature and combination of the materials used, can usually be defined as the ratio between the conditions. This ratio is also proportional to the inverse of the probability ( risk ) of failure of the structure.Failure has to be considered not only as overall collapse of the structure but also as unserviceability or, according to a more precise. Common definition. As the reaching of a “limit state ” which causes the construction not to accomplish the task it was designedfor. There are two categories of limit state :(1)Ultimate limit sate, which corresponds to the highest value of the load-bearing capacity. Examples include local buckling or global instability of the structure; failure of some sections and subsequent transformation of the structure into a mechanism; failure by fatigue; elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure; and sensitivity of the structure to alternating loads, to fire and to explosions.(2)Service limit states, which are functions of the use and durability of the structure. Examples include excessive deformations and displacements without instability; early or excessive cracks; large vibrations; and corrosion.Computational methods used to verify structures with respect to the different safety conditions can be separated into:(1)Deterministic methods, in which the main parameters are considered as nonrandom parameters.(2)Probabilistic methods, in which the main parameters are considered as random parameters.Alternatively, with respect to the different use of factors of safety, computational methods can be separated into:(1)Allowable stress method, in which the stresses computed under maximum loads are compared with the strength of the material reduced by given safety factors.(2)Limit states method, in which the structure may be proportioned on the basis of its maximum strength. This strength, as determined by rational analysis, shall not be less than that required to support a factored load equal to the sum of the factored live load and dead load ( ultimate state ).The stresses corresponding to working ( service ) conditions with unfactored live and dead loads are compared with prescribed values ( service limit state ) . From the four possible combinations of the first two and second two methods, we can obtain some useful computational methods. Generally, two combinations prevail:(1)deterministic methods, which make use of allowable stresses.(2)Probabilistic methods, which make use of limit states.The main advantage of probabilistic approaches is that, at least in theory, it is possible to scientifically take into account all random factors of safety, which are then combined to define the safety factor. probabilistic approaches depend upon :(1) Random distribution of strength of materials with respect to the conditions offabrication and erection ( scatter of the values of mechanical properties through out the structure );(2) Uncertainty of the geometry of the cross-section sand of the structure ( faults and imperfections due to fabrication and erection of the structure );(3) Uncertainty of the predicted live loads and dead loads acting on the structure;(4)Uncertainty related to the approximation of the computational method used ( deviation of the actual stresses from computed stresses ).Furthermore, probabilistic theories mean that the allowable risk can be based on several factors, such as :(1) Importance of the construction and gravity of the damage by its failure;(2)Number of human lives which can be threatened by this failure;(3)Possibility and/or likelihood of repairing the structure;(4) Predicted life of the structure.All these factors are related to economic and social considerations such as：(1) Initial cost of the construction;(2) Amortization funds for the duration of the construction;(3) Cost of physical and material damage due to the failure of the construction;(4) Adverse impact on society;(5) Moral and psychological views.The definition of all these parameters, for a given safety factor, allows construction at the optimum cost. However, the difficulty of carrying out a complete probabilistic analysis has to be taken into account. For such an analysis the laws of the distribution of the live load and its induced stresses, of the scatter of mechanical properties of materials, and of the geometry of the cross-sections and the structure have to be known. Furthermore, it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material, on the cross-sections and upon the load acting on the structure. These practical difficulties can be overcome in two ways. The first is to apply different safety factors to the material and to the loads, without necessarily adopting the probabilistic criterion. The second is an approximate probabilistic method which introduces some simplifying assumptions ( semi-probabilistic methods ) 。

毕业设计（论文）外文翻译题目地震荷载下的混凝土重力坝断裂原因分析专业水利水电工程班级2010级1班学生倪昌义指导教师陈野鹰重庆交通大学2014 年Fracture analysis of concrete gravity dam underearthquake induced loadsABBAS MANSOURI; MIR AHMAD LASHTEH NESHAEI; REZA AGHAJANY1 Civil Engineering, Islamic Azad University (South Branch of Tehran) Tehran, Iran2 Civil Engineering, University of Guilan, Rasht, Iran3 Civil Engineering, Islamic Azad University, (North Branch of Tehran), Tehran, Iran ABSTRACT: In this paper, seismic fracture behavior of the concrete gravity dam using finite element (2D) theory has been studied. Bazant model which is non-linear fracture mechanics criteria as a measure of growth and smeared crack was chosen to develop profiles of the crack. Behavior of stress - strain curves of concrete as a simplified two-line, dam and reservoir system using the formulation of the Euler-Lagrange was chosen. According to the above models, Koyna concrete gravity dam were investigated by the 1967 earthquake record. The results provide profiles of growth and expansion first with the effects of reservoir and second without it. Comparison of the obtained results shows good agreement with the works of the other researchers.Keywords: Seismic fracture; Smeared crack; Non-linear fracture mechanics; Concrete gravity dam.The seismic behavior of concrete dams has been the subject of extensive research during the past decade concerning dam safety during earthquakes. Chopra et al (1972), studies seismic behavior of dam’s crack path by using linear elastic analysis. The analysis shows, places that are in damage or and risk of the concerning stability of structure. Pal (1976) was the first researcher who examined Koyna dam by using non-linear analysis. In this research, assuming no effect of reservoir, being rigid foundation, smeared crack model use for crack expansion and strength criteria to crack growth, Koyna dam was analyzed and was shown that the results of material properties and element size are very sensitive. Figure 1(a) crack zone in the dam of which resulting from this analysis are shown. Skrikerud (1986) studied concrete dams through a case study on Koyna dam and by employing discrete crack for crack growth and strength criteria for crack expansion. In their study the growth of crack at each step of growth, the length of the crack tip element was considered that this is the final results were effective. He interpreted the results of their model, due to expansion mismatch with the cracking in their analysis of real crack in the dam, no match Foundation and reservoir interaction and lack of real values of characteristic parameters dam announced.Crack profiles from the analysis left in Figure 1(b) are presented. El-Aidi and Hall (1989) did a research on seismic fracture of Pine flat dam. Smeared crack model and strength criteria for crack expansion and growth were used. In their analysis is considering the reservoir –dam and foundation –dam interaction was crack profile presented. Figure 1(c), cracking in the dam will provide analysis. Fenves and Vargas-Loli also studied Pine flat dam by using fracture mechanics criteria for crack growth and smeared crack model to crack expand (Uang and Bertero,1990). They apply different coefficients of Taft earthquake record, regardless of the effect by foundation; Pine Flat dam in two cases with and without the effect of the reservoir was analyzed. In this study the effect of hydrodynamic pressure on the seismic behavior in the dam with the crack profiles presented. The results of this analysis were shown in Figure 1(d). Koy Koyna dam is one of a few concrete dams that haveexperienced a destructive earthquake. In this paper, study the nonlinear fracture behavior ofconcrete gravity dams under earthquake conditions. First, presented smeared crack modelwith the behavior of concrete under dynamic loads and fracture of dams. Secondly, Seismicbehavior of concrete gravity dams was assessed with non-linear analysis to Koyna dam withregard dam – reservoir interaction and without reservoir using finite element 2D method andpresented results of analysis. From the results it is concluded that both the upstream anddownstream faces of the dam are predicted to experience cracking through the upper part ofthe dam, which is consistent with the observed prototype behavior. Comparison analysis wasdone showed that the reservoir effect cannot be waived.(d) Vargas-loli (c) El-Aidi (b) Skrikerud (a) Pal(h) Experimental model (g) Real model (f) Bhattacharjee (e) Calayir anAnd Leger KaratonFigure 1: Past investigations into cracking profile in gravity dams.Euler - Lagrange Formulation for Dynamic Interaction of Dam - Reservoir Systems andBoundary Conditions: Different methods for dam and reservoir modeling are used. The Euler- Lagrange model is one criteria to used. In this research, the relations of Euler - Lagrangefor dam and reservoir modeling system is investigated.In Figure 2, the dam and reservoir boundary condition is presented.According to the finite element theory equations governing the dam is as follows(Kucukarslan, 2003):)1(}]{][[}]{[}]{[}]{[-----------------=++g a J M r K r C r MIn this equations,][M =Mass matrix,][C =Damping matrix,][K = Structural stiffnessmatrix,}{r =Displacement vector of relative nodal,][J = Unit matrix,}{a g = Anchoracceleration vector.Equation governing the distribution of hydrodynamic pressure in the fluid environment iswell known Helmholtz equation by two relations in which presented by the equation below: )2(2222----------------------∂∂=t P C P VI n Equation (2), =p the fluid pressures, =C the speed of sound in the fluid.Four boundary conditions are used to define the reservoir as follows.1. Free surface Boundary)3(0--------------------------=p2. Remote Boundary)4(12------------------------=∂∂p cn p 3. Interaction Boundary)5(------------------------=∂∂n s pa n p 4. Bottom Boundary)6(--------------------∂∂--=∂∂tp q a n p n g ρ In this Equations,=n s a Dam Acceleration,=n g a Ground Acceleration,=n Vectorperpendicular,=ρFluid density. Value of acceleration created in the reservoir, is related tothe amount of dam acceleration.,221c q ρρ=where:=1ρfluid density,=2ρDamdensity,=2c speed of sound.Considering the boundary conditions and fluid equations, the relationship matrix in thereservoir is formed as follows:)7(}}{]{[}]{[}]{[}]{[-------------=++g a J B p H p L p GFigure 2: dam and reservoir Systems Where:=][G Fluid mass matrix,=][L Damping matrix,=][H Fluid stiffnessmatrix,=}{p Hydrodynamic pressure vector,=}{J Unit matrix,=}{g a Anchor Accelerationvector.Rupture direction, is defined by potential derivative according to stress or strain tensor.Loss potential can be either a function of stress or strain (Kolari, 2007). In smeared crackmodel, loss potential is a function of stress. This means that crack happens when the stressesreach the level of submission. Also crack levels which are perpendicular to the maximum, are regarded as the tensile main stress. As a result in the state of compressive stress, no damage is recorded.As stress increases inelastic strains happen and concrete becomes soft. At any point, after the maximum compressive strength of concrete, initial slope is parallel to loading slope. When the unloading direction changes (strain - stress) the concrete response is to the maximum elastic tensile stress and then crack mechanism occurs. Than as a result concrete is damaged. In this state, with the help of reducing elastic hardness, a model can be made out of crack unfolding. If the compressive stress is applied again, by returning to zero, the cracks will be closed completely. Figure 3 shows the behavior of concrete when placed under compressive and tensile stress.Figure 3: Uniaxial behavior of plain concrete (Abaqus theory manual, 2009).According linear elastic fracture mechanics criteria, development process of crac k and its growth occur only at the peak of crack and the rest of elastic element rem ains and behaves linearly. This method is applicable in ordinary structure in which d amaged area is relatively small. But using nonlinear fracture mechanics model is mor e suitable in huge structures such as concrete dams where the damaged area is relati vely big. This method is established on the base of energy relations. In the field of fracture mechanics two models have been presented based on Hillerborg (1978) and Bazant (1983) theories. According to the model presented by Hillerborg in 1976, dam aged area is considered as imaginary crack at the peak of the real crack. In 1983; B azant showed that growth and expansion process of crack occur on a stripe. In the p resent study, Bazant smeared crack model is used in studying Koyna dam. ConclusionIn this research interaction of dam and reservoir under earthquake was examined by employing nonlinear fracture mechanics criterion and smeared crack model of develop profiles of the crack. The results, through analysis in conditions of dam decomposition with reservoir and without it, the following conclusions were reached:1、By comparing the results with other researchers it shows a fairly good agreement between this study and the others references: (Guanglun et al, 2000), (Calayir and Karaton, 2005), (Cai et al, 2008), (Hal, 1988), (Saini and Krishna, 1974), and therefore the philosophy of the nonlinear fracture mechanics criteria and smeared crack models at proper seismic behavior of concrete gravity dam seems to be confirmed. The obtained results of the analysisof Koyna dam considering interaction between dam and reservoir shows there are three vulnerable points: dam heels, changing areas of slope and some areas in upper part in which there are most of the crack elements. The results obtained in the analysis of Koyna dam regardless of reservoir effect on the dam, shows cracks in the heel areas of the dam, where the slope change. The results from analyses can be seen in damaged areas and the number of damaged elements in the case of interaction between dam and reservoir intended effect was bigger than effect of dam alone. Therefore it is important to attend thehydrodynamic pressure on concrete dam.2、Dynamic analysis was used in the smeared crack to extend crack and the non-linear fracture mechanics criteria for crack growth profiles is indeed the function of profile material, especially fracture energy and behavior of materials.3、Being given specific structures such as concrete gravity dam, which provide great scope area for fracture energy according to the various references and considering the importance of this parameter with the behavior of materials in the behavior of seismic fracture dams, Accurate tests, and also correct definition of material behavior are a necessity. The theory of nonlinear fracture mechanics for defining the fracture area and smeared crack model for defining the develop crack, can be regarded as a proper criterion and provides us with the real behavior of the structure.ReferencesAbaqus theory manual and users' manual, (2009).Bazant, Z. P. and oh, B. H (1983). “Crack band theory for fracture of concrete.” Materials and Structure.Bhattacharjee, S. S. and Leger, P (1992). “Concrete constitutive models for nonlinear seismic analysis of gravity dams-state-of-the art.” Canadian Journal of Civil Engineering. Bhattacharjee, S. S. and Leger, P (1994). “Application of NLFM models to predict cra cking in concrete gravity dams.” Journal of Structural Engineering.Cai, Q. and Robberts, J.M. and Van Rensburg, B.W.J (2008). “ Finite element fracture modeling of concrete gravity dams. ”Journal of the South African Institution of Civil Engineering.Calayir, Y. and Karaton, M (2005). “Seismic fracture analysis of concrete gravity dams including dam–reservoir inter action.” Computers and Structures.Chopra, A. K. and Chakrabarti, P (1972). “The earthquake experience at Koyna dam and stress in concrete gravity dam. ” Earthquake Engineering and Structural Dynamic. Chopra, A.K (1967). “Hydrodynamic pressure on dams during earthquake,”Journal of Engineering Mechanics Division.El-Aidi, B. and Hall, J (1989). “Nonlinear earthquake response of concrete gravity dams”part 2: behavior.Gha emian, M. and Ghobarah, A (1999). “ Nonlinear Seismic Response of Concrete Gravity Dams With Dam –Reservoir Interaction.” Engineering Structures.Guanglun, W. and Pekau, O.A, and Chuhan, Z. And Shaomin, W (2000). “Seismic fracture analysis of concrete gravity dams based o n nonlinear fracture mechanics.”Engineering Fracture Mechanics.地震载荷下的混凝土重力坝断裂原因分析ABBAS MANSOURI;MIR AHMAD LASHTEH NESHAEI;REZA AGHAJANY1伊斯兰阿扎德大学，土木工程，伊朗德黑兰2桂兰大学，土木工程，拉什特，土木工程伊朗3伊斯兰阿扎德大学，土木工程，德黑兰（北支），伊朗摘要：在本文中，对混凝土重力坝的地震裂缝采用有限元（2D）的行为理论进行了研究。

Lesson 13 concrete gravity dam on rock foundations 岩基上的混凝土重力坝The designer of any dam must make basi c assumptions regarding site conditions and their effects on the proposed structure. 设计人员在设计任何坝时，都必须对有关坝址的情况及其对结构物的影响做出一些基本假定。

Site investigations provide the engineer with much of the information to evaluate these assumptions, the bases for safe dam design. 坝址的查勘为工程师拟定这些假定提供了许多资料。

这些假定是安全设计的基础。

Some important assumptions for small dam design involve uplift pressure, seepage control measures, channel degradation and downstream toe erosion, foundation conditions, and quality of construction. 有关小坝设计的一些主要假定包括：扬压力，渗流控制措施，河槽冲刷深度以及下游坝趾的冲蚀，坝基条件和施工质量。

Additional assumptions should involve silt loads, ice pressures, earthquake accelerations, and wave forces.其它一些附加假定应包括泥沙荷载、冰压力、地震加速度和波浪力。

1 safety factors 安全系数Safety factors should be considered in the light of economic conditions. Large safety factors result in a more costly structure; however, low safety factors may result in failure, which could also lead to high cost.安全系数应根据经济情况来考虑。

本科生文献翻译题目重力坝设计学院水利水电学院专业水利水电工程学生姓名王程学号 2012141482047 年级2012 级指导教师李艳玲教务处制表二Ο一六年六月三日Design of Gravity DamsA gravity dam is a concrete structure which resists the imposed forces by its weight and section without relying on arch or beam action. In its common usage the term is restricted to solid masonry or concrete dams which are straight or slightly curved in plan.The downstream face of gravity dam is usually of uniform slope which if extende d, would intersect the upstream face at or near the maximum reservoir level. The upstream face is normally vertical excepting for steep batter near the heel. The upper portion is usually thick enough to resist the impact of floating objects and accommodate a roadway. The thickness of section at any elevation is adequate to resist sliding and to ensure compressive stresses at the heel under different conditions of loading.For a gravity dam to be stable, the following criteria should be satisfied:1) Resultant of all static and pseudo-static forces should lie within the middle third lines or the kern of the dam at all section. This ensures a factor of safety of about 2 against overturning and eliminates tensile stresses at the heel and the toe of the dam.2) The dam should provide adequate factor of safety against sliding at the construction joints, the base of the dam, and any planes of weakness within the foundation.3) Maximum stresses in the dam section and the foundation should be within the permissible stresses of the concrete used in the dam section and the foundation rock respectively.Gravity dams can be analyzed by the Gravity Methods, Trial-load Twist Analysis, or the Beam and Cantilever Method, depending upon the configuration of the dam, continuity between the blocks, and the degree of refinement required. The Gravity method is used when blocks are not made monolithic by keying and grouting the joints between them. Thus, each block acts independently and the load is transmitted to the foundation by cantilever action and is resisted by the weight of the cantilever. Trial-load twist analysis and the beam and cantilever analysis are used when the blocks are keyed and grouted together to form a monolith because part of the load is transmitted to the abutments by beam action. The Gravity Method may be used, however, as a preliminary analysis for keyed and grouted dams.The Gravity Method is applicable to the general case of a gravity section with vertical upstream face and a constant downstream slope and to the case where there is variable batter on either or both faces. The method provide a direct method of calculating stresses at any point within the boundaries of a transverse section of a gravity dam, and the results are substantially correct, except for horizontal planes near the base of the dam where the foundation yielding affects the stress distributions. The stress changes which occur due to foundation yielding are usually small in dams of low or medium height but they may be important in high dams. Stresses near the base of a high masonry dam should be checked by the Finite Element Method or other comparable methods of analyses.Uplift pressures on a horizontal section are usually not included with the contact pressures in the computation of stresses, but are considered in the computation of stability factors.The analysis of overflow sections presents no added difficulties. Usually, the dynamic effect of overflowing water is negligible and can be omitted. Any additional head above the top of the section can be included as a surcharge load on the dam.The following are assumptions to the Gravity Method:l) The concrete in the dam is a homogenous, isotropic, and uniform elastic material.2) There are no differential movements which occur at the dam site due to water loads on the reservoir walls and floors.3) All loads are carried by the gravity action of vertical, parallel side cantilever which receive no support from the adjacent elements on either side.4) Unit vertical pressures, or normal stresses on horizontal planes, vary uniformly as a straight line from the upstream face to the downstream face.Shear-friction factor are computed at each elevation for which stresses are calculated in the cantilever element. All possible conditions of loading should be investigated. It should be noted that a large margin of safety against sliding is indicated by high shear-friction factor.A factor of safety for overturning is not usually tabulated with other stability factors. Before bodily overturning of a gravity dam can take place, other failures may occur such as crushing of the toe material and cracking of the upstream material with accompanying increases in uplift pressure and reduction of the shear resistance. How-ever, it is desirable to provide an adequate factor of safety against the overturning tendency. This may be accomplished by specifying the maximum allowable stress at the downstream face of the dam.Because of their oscillatory nature, earthquake forces are not considered as contributing to the overturning tendency. A factor of safety for overturning may be calculated if desired by dividing the total resisting moments by the total moments tending to cause overturning about the downstream toe?Design of Earth DamsIn general, there are two types of embankment dams: earth and rockfill. The selection is dependent upon the usable materials from the required excavation and available borrow. There is no typical earth dam. All are designed and constructed to meet the condition at each particular site. However, there are certain general similarities which permit presentation of types of designs, for example, the earth dam can be further classified into three basic types according to the location of impervious zone: homogeneous dam, central core dam, inclined core dam. The selection and the design of an earth dam are based upon the judgment and experience of the designer and is to a large extent of an empirical nature. The various methods of stability and seepage analyses are used mainly to confirm the engineer's judgment.For an earth dam to be stable, the following criteria should be satisfied: (1)The foundations, abutments and the earth dam must be stable for all conditions of construction a nd operations; (2) Seepage through the dam, foundation and abutment must not exert excessive forces which will result in instability of the dam or abutments while piping, if not controlled, will eventually result in the release of the pool; (3) The top of the dam must be high enough to allow for settlement of the dam and foundation and also to provide sufficient freeboard to prevent waves from a maximum pool from overtopping the dam; (4) The spillway and outlet capacity must be such as to prevent overtopping of the dam; (5)The slopes of the spillway and the outlet works must be stable under all operational conditions.The foundation, abutments and potential sources of borrow materials for construction of the dam must be studied in detail. The influence must be considered of seismic action on thestability of the dam, the abutments, the cut slopes of the spillway and inlet and outlet works, and especially induced liquefaction.In the design of an earth dam, the following aspects should be considered carefully:1) Freeboard. All earth dams must have sufficient extra height known as freeboard to prevent overtopping by the pool. The freeboard must be of such height that wave action, wind setup, and earthquake effects will not result in overtopping of the dam. In addition to freeboard, an allowance must be made for settlement of the dam and the foundation which will occur upon completion of the dam. An extra allowance for freeboard to counter earthquake induced settlement is required.2) Top Width. The width of the earth dam top is generally controlled by the required width of fill for ease of construction using conventional equipment. If a highway is to cross the dam then this will control the top width.3) Alignment. The alignment of an earth dam should be such as to minimize construction costs but such alignment should not be such as to encourage sliding or cracking of the dam? Normally the shortest straight line across the valley will be satisfactory, but local topographic and foundation conditions may dictate otherwise.4) Abutments. Three problems are generally associated with the abutment of earth dams: (1) seepage, (2) instability, and (3) transverse cracking of the dam. If the abutment consists of deposits of previous soils it may be necessary to construct an upstream impervious blanket and downstream drainage measures to minimize and control abutment seepage. If the abutments are weak then the embankment fill may be widened to provide a support to prevent sliding under the action of downstream seepage and upstream pool drawdown. Where steep abutments exist, especially with sudden changes of slopes or with steep bluff, there exists a danger of transverse cracking of the embankment fills. This can be treated by excavation of the abutment to reduce the. slope, especially in the imperious and transition zones. Surface drainage should be provided at the junction of the fill and abutments to avoid rain and snow melt nm-off erosion.5) Stage Construction. It is often possible, and in some cases necessary, to construct the dam in stages. Factors dictating such a procedure are (1) a wide valley permitting the construction of the diversion or outlet works and part of the embankment at the same time; (2) a weak foundation requiring that the embankment not be built too rapidly to prevent overstressing the foundation soils; (3) a wet borrow area which requires a slow construction to permit an increase in shear strength through consolidation of the fill.6) River Diversion. The diversion of the river is a critical operation in the erection of an earth dam and the timing and method are significant parts of design. The factors affecting the method of river diversion are hydrology, site topography, geology and construction programming. The diversion works must be constructed first. Once diversion has been made, the permanent cofferdams are constructed; the most important of which is the upstream. If the upstream cofferdam top is wide, or if a significant part of the closure has been constructed and a danger of overtopping exists, then consideration should be given to using the part of the downstream fill as a temporary source of borrow to quickly raise the cofferdam.7) Seismic Problems. An earth dam should never be located on or near an active fault. It is often necessary, however, to construct dams in seismically active areas and for these cases defensive design measures should be taken. These consist of (1) not building upon loosefoundation sands; (2) the impervious zone should be made plastic by compacting at a somewhat higher water content; (3) enlarging the impervious core; (4) flattening the outer slopes; (5) increasing the height of the dam to allow for seismically induced settlement; (6) increasing the width of the crown; (7) increasing the widths of the falter zones and constructing the upstream zones of cohesionless soils which will readily move into any downstream cracks;(8) increasing the width of the zones at the abutments.8) Cracking Problems. The design and construction of an earth dam should be such as to prevent cracking, especially transverse cracks which may lead to failure by piping.9) Seepage Control. Seepage is prevented or minimized by an impervious zone located in the central or upstream part of the dam. If the embankment rests upon a pervious foundation, then a cutoff may be used or if the foundation is too thick, then a slurry trench or an up-stream impervious blanket is used. The impervious zone is supported by up and downstream shells. The shell may be either pervious or random depending upon available soils.Seepage through the earth dam is collected by either a pervious downstream shell or by a combined inclined and horizontal drainage blanket. The capacity of the drain should be sufficient to carry off the collected seepage with little head loss. Collector pipes should not be used in or under the main body of the embankment. Collector pipes should be located at the downstream toe of the drainage blanket where it can be readily reached for maintenance and repairs. The drainage material must meet the filter requirements to prevent the finer adjacent soils from being carried into the drain.10) Excess Pore Pressures. The influence of foundation settlement and its rate must be considered. Foundation settlement will require overbuilding of the dam to allow for post construction settlement to provide an adequate freeboard. If compressible soils are present then consolidation tests must be made to permit an estimate of the rate at which the excess water will be expelled. The gain in shear strength of the foundation is dependent upon the rapidity of consolidation. If the rate is slow then the stresses induced in the foundation by the earth dam will be carried partly by the soil structure and partly by the pore water. If the foundation's shear strength is low then the rapidity of earth dam construction must be controlled by stage construction-the outer slope flattened or stability berms used. The rate at which the consolidation occurs may be accelerated through use of horizontal drainage layers and by vertical sand drains. Because of the variation of natural soils and the simplifying assumptions made in the shearing and consolidation theories, a conservative approach to the selection of design shear strengths is necessary.As a result of experiences with the earlier concrete-faced rockfill dams, a number of changes in design treatment and construction practice have evolved in recent years: (1) Compacted rockfill, rolled in compacted rockfill thin layers, has practically superseded dumped rock placed in high ~lifts. It is now almost universally used in the main rockfill sections of rolled in thin layer modem dams. (2) The upstream dry rubble masonry or placed-rock zone is no longer used. The upstream slopes are constructed at or about the normal angle of repose of the rock, and a compacted bedding layer of small rock is placed on the upstream face to support the facing. (3) Cutoff walls deeply entrenched into the rock have largely been superseded by anchored footwalls which support and seal the periphery of the facing and serve as a grout cap for curtain grouting.(4)The present trend is toward the elimination of deformable joint fillers in vertical joints of thefacing and very limited use of horizontal joints.Some or all of these design and construction modernizations have been utilized in the two dams selected as examples in the following brief discussions,Cethana DamIt is 110 m high, completed in 1971. The upstream slopes are 1.3 H to 1.0 V. The main rockfill was sound quartzite. The rock was placed in layers 0.9 m thick and rolled with 4 passes of a 10-ton vibratory roller. Immediately preceding and during compaction all rockfill was sprayed with water, the volume applied being not less than 15 percent of the rockfill volume. This procedure produced a relative density of the rockfill close to 100 percent. Within the downstream one-third of the section, lifts 1.35 m thick were used and the gradation limits for the rockfill were wider than for the main rockfill. A zone about 3.0 m wide in the upstream part of the main fill was composed of specially selected rock and compacted in 0.45 m lifts.To ensure good compaction of the fill immediately beneath the facing, the upstream face of the rockfill was initially given 4 passes of the miler without vibration, and the slope was trimmed to remove high spots. It was then given 4 passes at half vibration and low areas were filled. To avoid displacement of stones by roller vibration, traffic, and rain, a bitumen emulsion treatment was applied. The final compaction was attained by 8 passes of the roller with full vibration.The concrete facing was slip formed in panels 12.2 m wide with horizontal contraction joints except near the periphery where intermediate vertical joints, terminating in horizontal contraction joints, were introduced to control cracking of the slab in zones where horizontal tensile strains were expected.~ These horizontal joints contained wood filler strips, but no filler of any kind was used in the vertical joints. The concrete facing was tapered according to the formula "t = 0.3+0.002 h", where "t'= thickness and "h'= hydraulic head, in meters. The plinth or footwall at the lower periphery of the facing was not entrenched but cast on the rock surface after removal of weathered and open jointed rock. The plinth was dowelled to the foundation to withstand the consolidation grouting pressures.Instrumentation installed at Cethana provided comprehensive data on the structure during construction, first filling of the reservoir, and for a short period of operation. A few of the findings are cited for comparison with performance data on dumped rockfill dams:1) During construction, settlement was approximately proportional to height of rockfill when rock was placed continuously. Creep settlement continued with no increase in fill loading.A high rate of settlement continued for up to 2 months after the top 12 m of rockfill was placed and after the reservoir was filled.2) The vertical and horizontal deflections of the crest during a period of about 11 months following the commencement of filling the reservoir were: maximum vertical = 69 mm, horizontal down-stream maximum = 41 mm, horizontal transverse = 18 mm toward center from left and 8 mm toward center from right.3) The deflection of the membrane was essentially normal to the face and was a maximum of about 13 mm at about the lower 0.4 point of the slope.4) The maximum perimetric joint opening was about 11.5 mm.5) After filling the reservoir the strains in the facing were compressive, the maximum being 207×106 in the slope direction and 290×106 in the transverse direction.6) The leakage past the dam at full reservoir was 0.035 m3/s.New Exchequer DamIt is 149.5 m high, completed in 1966. The dam is unique in that it incorporates the old 94.55 m high concrete gravity arch dam in the upstream heel as a retaining wall for the rockfill of the new dam, and as the lower part of the upstream impervious membrane on the face of the new dam. The slopes of the dam, both upstream and down-stream, are 1.4 H to 1.0 V. The rockfill was placed in 4 zones, as follows:1) The zone immediately under the concrete facing consists of 38.1 cm maximum size rock compacted in 0.61 m lifts by a 10-ton vibratory rollers.2) An upstream zone adjacent to the old dam and extending to the top of the new dam, varying in width from about 61 m at the bottom to about 12.2 m at the top, was constructed of 1.22 m maximum size rock placed in 1.22 m lifts and compacted by 10-ton rollers.3) The main body of the dam consist~ of 1.22 m maximum size rock placed in 3.1 m lifts and compacted by hauling and grading equipment.4) The downstream slope section of the dam consists of largest rock which could be placed with a minimum of 50 percent larger than 30.48 m. The fill material was dumped in lifts up to 18.3 m high but no compaction was specified. All the fill except the zone immediately under the facing was sluiced with high pressure jets.The New Exchequer Dam rockfill represents a compromise or transition between the traditional practice of dumping rock in high lifts without compaction and the more recent trend toward heavy mechanical compaction of the flu in relatively thin lifts.Measurements made during construction and during the first filling of the reservoir showed normal movements of the facing slabs, with the vertical joints near the center tending to close and those near the abutments tending to open. After the reservoir was filled the maximum crest settlement was 0.46 m or about 0.3 percent of the height. The maximum horizontal downstream movement of the crest was 12.2cm or about 30 percent of the associated vertical movement. The crest settlement was only about one-third of that which normally would have been expected for a dumped rockfill, but about 5 times that of the fully compacted rockfill of Cethana Dam. The settlement of the facing itself formed the characteristic bowl-shaped depression with a maximumdepth of about 61cra normal to the slope at a point 0.3 to 0.4 of the height above the toe?During the first two fillings of the reservoir the leakage through the dam increased from 0.35 m3/sec to a maximum of 13.72 m3/sec. This was caused by the spalling and cracking of the face slabs at and near the junction of the new facing with the old dam. A supplementary zone composed of sand, gravel, clay, and bentonite was placed underwater in the "V" notch formed at the contact of the new facing with the downstream facing of the old dam. This material was placed to a depth of 6.1 m to 7.6 m using a specially designed skip? The sealing blanket reduced the leakage to about 0.224 m3/sec.重力坝设计重力坝是通过其自重和截面，而不依赖于拱和梁的作用来抵抗强加的外力的一种混凝土结构。

外文文献及译文目录•1历史•2组成o水泥2.1o 2.2水o 2.3骨料o 2.4化学外加剂o 2.5掺合料和水泥混合o 2.6纤维•3搅拌混凝土•4个特点o 4.1和易o 4.2固化o 4.3强度o 4.4弹性o 4.5扩张和收缩o 4.6开裂▪ 4.6.1收缩裂缝▪ 4.6.2拉裂o 4.7蠕变•5损伤模式o 5.1火灾o 5.2总量扩张o 5.3海水效果o 5.4细菌腐蚀o 5.5化学武器袭击▪ 5.5.1碳化▪ 5.5.2氯化物▪ 5.5.3硫酸盐o 5.6浸出o 5.7人身损害•6种混凝土o 6.1普通混凝土o 6.2高强混凝土o 6.3高性能混凝土o 6.4自密实混凝土o 6.5喷浆o 6.6透水性混凝土o 6.7混凝土蜂窝o 6.8软木复合水泥o 6.9碾压混凝土o 6.10玻璃混凝土o 6.11沥青混凝土•7混凝土测试•8混凝土回收•9使用混凝土结构o9.1大体积混凝土结构o9.2钢筋混凝土结构o9.3预应力混凝土结构•10参见•11参考•12外部链接历史在塞尔维亚,仍然是一个小屋追溯到5600bce已经发现,同一个楼层发红色石灰,沙子和砾石。

金字塔陕西中建千多年前,含有石灰和火山灰.或粘土。

碎石水和泥浆僵硬和发展实力超过时间。

为了确保经济实用的解决方案,既罚款又粗骨料使用,以弥补大部分的混凝土混合物。

砂,天然砾石及碎石,主要用于这一目的。

不过,现在越来越普遍,再生骨料(由建筑,拆卸和挖掘废物)被用作局部代替天然骨料,而一些生产总量包括风冷高炉炉渣和粉煤灰也是不允许的。

装饰石材等石英岩,潆石块或玻璃破碎,有时添加到混凝土表面进行装饰性"的总暴露"完成,流行景观设计师。

化学外加剂化学外加剂现形式的材料粉末或液体,补充了混凝土给它的某些特性没有可与普通混凝土混合物。

在正常情况下使用,外加剂剂量均低于5%的大量水泥,并补充了混凝土当时的配料/混合.最常见的外加剂有:加速器加速水化(硬化)的混凝土。