08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 (1)

水利水电专业毕业论文文献翻译坝（可编辑）水利水电专业毕业论文文献翻译坝Dam The first dam for which there are reliable records was build or the Nile River sometime before 4000 B.C. 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 U.S.S.R. on the vaksh River near the border of Afghanistan. This dam will be 1017ft333m 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 PL92-367requires 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 waterbehind 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 includedin 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 adecade or longer after the first stage The height of a dam isdefined 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.2.Forced on dams A 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 component of the hydrostatic force is the force or unit width of dam it is Where 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 the dam .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 ofgravity of this volume of water Water under pressure inevitablyfinds 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 atthe upstream face heelto full tail-water pressure at the downstream face toe.For this assumption the uplift force U is Urh1+h2t/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 byEq.2Various assumption have been made regarding the distribution ofuplift pressures.The ////0>. 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。

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。

混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译) Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons,however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials arematerials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends underthe heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cementswhen ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to theconcrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it isembedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable untileventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。

毕业设计（论文）外文翻译题目榆林王圪堵水库枢纽布置及重力坝设计专业水利水电工程班级学生指导教师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 AGHAJANY 1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。

巴占特模型（它是非线性的断裂力学标准作为衡量的增长和弥散裂缝）被选中来开发裂缝的剖面图。

混凝土的应力-应变曲线作为简化的两线，欧拉-拉格朗日公式被选用于大坝和水库系统。

根据1967年的地震记录，用上述模型对Koyna混凝土重力坝进行了研究。

结果证实了第一个裂缝的图像有增长和扩张而第二个并没有受到它的影响。

比较的结果显示了与其他研究者一致的结论。

关键词：地震断裂；弥散裂缝；非线性断裂力学；混凝土重力坝。

在过去的十年里，有关在地震时混凝土大坝安全的的大坝抗震性能已受到广泛的研究。

Chopra 等人(1972),通过使用线性弹性分析研究大坝的抗震性能的裂纹路径。

分析显示,在损坏或有风险的地方会影响结构的稳定性。

Pal(1976)是第一个利用非线性分析研究Koyna大坝的研究人员。

在本研究中,假设没有水库的影响,在刚性地基上,用弥散裂纹模型对Koyna 大坝裂纹扩张和强度标准裂纹增长进行了分析。

结果表明,裂纹的增长对材料性质以及元素大小是非常敏感的。

图1(a)显示了这种分析造成的大坝裂纹区。

Skrikerud（1986）采用离散裂缝裂纹扩展和裂纹增长的标准，通过Koyna大坝的个案研究了混凝土坝。

在他们的研究中，裂纹在每一步的成长,长裂纹尖端的元素最终被认为是有效的。

他把他们的模型试验结果归结于裂纹分析在与大坝开裂的膨胀系数不匹配、和水库相互作用并且缺乏大坝特性参数的实际值等原因。

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。

混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译)Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons, however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials are materials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends under the heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cements when ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to the concrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it is embedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable until eventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。

混凝土重力坝对承受时间方法在地震分析中的应用V. Valamanesh, H.E. Estekanchi A. Vafai, M. Ghaemian关键字:持续时间的方法;加速度函数;混凝土重力坝;地震分析摘要:本文应用对混凝土重力坝抗震分析的续航时间（ ET ）的方法进行了研究。

ET方法是基于结构的时程，经过特别设计的加强加速功能进行分析。

预计通过开发，其在分析混凝土坝对这类水坝的有用的抗震性能的应用并得到各种激发强度。

结果从佛森和科依纳水库线性分析在实际地震和ET加速功能进行了比较。

它表明，ET方法可以合理准确的预测混凝土重力坝个别地震响应的线性分析。

通过线性分析，以评估混凝土重力坝，目标时间已假定对应于地震OBE水平。

耐久性标准可以被设置为时间时所需的损伤指数（ ES ），例如最大主应力，达到其允许值。

如果续航时间超过目标时间，设计可以被认为是令人满意的，反之亦然。

此外，潜在的应用对混凝土重力坝非线性分析的ET方法进行了研究。

这表明，地震破裂分布可以通过追踪采用ET方法。

1.介绍抗震设计的基本目标是在经受强烈地震的结构，其相应的故障安全边际。

混凝土大坝高重要性的结构，就其一生中需要连续服务，并在普罗巴-BLE溃坝情况下的灾难性后果之一。

因此，这些结构的安全，应可以通过逻辑和精确的方法严格调查。

在续航时间过程中，结构受到一组专门设计的加强的加速度，其中反应谱随着时间的推移成比例增加，并在该时间间隔期间根据测得结构的耐久时间，他们可以抵抗施加的动态激励。

在本文中，使用ET的方法，并考虑弹性分析过程中，两个动态性能在众所周知操作下基于地震混凝土坝（OBE）进行了评价。

对ET过程的基本知识进行了简要检讨。

在实际地震，续航时间的分析结果的福尔瑟姆和科依纳水库，根据ET加速功能并考虑到大坝水库的相互作用，已提交和相比，相当于响应的频谱分析并且还时程分析。

在非线性分析，采用弥散裂缝的方法，根据ET加速科依纳水库的表现功能进行了研究，并在ET方法的潜在混凝土坝非线性分析进行评价。

文献出自：Gimenes E, Fernández G. Hydromechanical analysis of flow behavior in concrete gravity dam foundations[J]. Canadian geotechnical journal, 2006, 43(3): 244-259.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。

Chapter 5Static and Dynamic Stress Analysis第五章静态和动态应力分析5-1. Stress Analysis5-1.应力分析a. General.(1) A stress analysis of gravity dams is performed to determine the magnitude and distribution of stresses throughout the structure for static and dynamic load conditions and to investigate the structural adequacy of the substructance and foundation. Load conditions usually investigated are outlined in Chapter 4.(2) Gravity dam stresses are analyzed by either approximate simplified methods or the finite element method depending on the refinement required for the particular level of design and the type and configuration of the dam. For preliminary designs, simplified methods using cantilever beam models for two-dimensional analysis or the trial load twist method for three-dimensional analysis are appropriate as described in the US Bureau of Reclamation (USBR), “Design of Gravity Dams” (1976).The finite element method is ordinarily used for the feature and final design stages if a more exact stress investigation is required.a.普通方法(1)重力坝的应力分析是用以确定在静态和动态荷载作用下结构的应力分布和大小情况以及验证下部和基础的结构强度，荷载条件通常在第四章作了概述。

毕业设计（论文）外文翻译题目水库及电力系统简介专业水利水电工程班级2007级四班学生陈剑锋指导教师杨忠超重庆交通大学2011 年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 anuncontrolled 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.水库拦河筑一条像坝的障碍时，水就被拦蓄在障碍物的上游并形成水塘．通常称之为水库。