Tunnelling Methods

NATM tunnel design principle in the construction of major andConstruction TechnologyW.BroereI.The NATM Design Principle1.Tunnel design and construction of two major theoretical and development processSince the 20th century, human space on the ground floor of the growing demand, thus the underground works of the study of a rapid development. In a large number of underground engineering practice, it is generally recognized that the tunnel and underground cavern project, the core of the problem, all up in the excavation and retaining two key processes. How excavation, it will be more conducive to the stability and cavern facilitate support : For more support, Supporting how they can more effectively ensure stability and facilitate the cavern excavation. This is the tunnels and underground works two promote each other and check each other's problems.Tunnels and underground caverns, and focusing on the core issues with the above practice and research, in different periods, People of different theories and gradually established a system of different theories, Each system includes theory and resolve (or are studying the resolution) from the works of understanding (concept), mechanics, engineering measures to the construction methods (Technology), a series of engineering problems.A theory of the 20th century the 1920s the traditional "load relaxation theory." Its core content is : a stable rock self-stability, no load : unstable rock may have collapsed. need shoring structure to be supported. Thus, the role of the supporting structure of the rock load is within a certain range may be due to relaxation and collapse of rock gravity. This is a traditional theory, and their representative is Taishaji and Principe's and others. It works similar to the surface issues of the thinking is still widely used to.Another theory of the 20th century made the 1950s the modern theory of timbering or "rock for the theory." Its core content is : rock stability is clearly bearing rock to their own self-stability : unstable rock loss of stability is a process, and if this process in providing thenecessary help or restrictions will still be able to enter the rock steady state. This theoretical system of representative characters Labuxiweici, Miller-Feiqieer, Fenner - Daluobo and Kashitenai others. This is a more modern theory, it is already out of the ground works to consider the ideas, and underground works closer to reality, the past 50 years has been widely accepted and applied. demonstrated broad development prospects.Can be seen from the above, the former theory more attention to the findings and the results of treatment : The latter theory is even more attention to the process and the control of the process, right from the rock for the full utilization of capacity. Given this distinction, which both theory and methods in the process, each with different performance characteristics. NATM theory is rock for the tunnel engineering practice in the representation method.2. NATMNATM that the new Austrian Tunneling Method short the original is in New Austrian Tunneling Method, referred to as the NATM. France said it convergence bound or some countries alleged to observe the dynamic design and construction of the basic principles.NATM concept of filibustering Xiweici Austria scholars in the 20th century, Professor age of 50. It was based on the experience of both the tunnel and rock mechanics theory, will bolt and shotcrete combination as a major means of supporting a construction method, Austria, Sweden, Italy and other countries, many practical and theoretical study in the 1960s and patented officially named. Following this approach in Western Europe, Scandinavia, the United States and Japan and many other underground works with a very rapid development, have become modern tunnels new technologies landmark. Nearly 40 years ago, the railway sector through research, design, construction combining, in many construction of the tunnel, according to their own characteristics successfully applied a new Austrian law, made more experience, have accumulated large amounts of data, This is the application stage. However, in the road sector NATM of only 50%. Currently, the New Austrian Tunneling Method almost become weak and broken rock section of a tunnel construction method, technical and economic benefits are clear. NATM the basic points can be summarized as follows : （1）. Rock tunnel structure is the main loading unit, the construction must fully protect the rock, it minimize the disturbance to avoid excessive damage to the intensity of rock. Tothis end, the construction of sub-section should not block too much, excavation should be used smooth blasting, presplit blasting or mechanical tunneling.（2）. In order to give full play to rock the carrying capacity should be allowed to control and rock deformation. While allowing deformation, which can be a rock bearing ring; The other hand, have to limit it, Rock is not so lax and excessive loss or greatly reduced carrying capacity. During construction should be used with rock close to, the timely building puzzle keeps strengthening Flexible support structure, such as bolting and shotcreting supporting. This adjustment will be adopted supporting structural strength, Stiffness and its participation in the work of the time (including the closure of time) to control the deformation of the rock mass.（3）. In order to improve the support structure, the mechanical properties, the construction should be closed as soon as possible, and to become a closed cylindrical structure. In addition, the tunnel shape with a round should, as far as possible, to avoid the corner of the stress concentration.（4）. Construction right through the rock and supporting the dynamic observation, measurement, and reasonable arrangements for the construction procedures, changes in the design and construction management of the day-to-day.（5）. To lay waterproof layer, or is subject to bolt corrosion, deterioration of rock properties, rheological, swelling caused by the follow-up to load, use composite lining.（6）. Lining in principle, and the early rock deformation Supporting the basic stability of the conditions under construction. rock and supporting structure into a whole, thereby improving the support system of security.NATM above the basic elements can be briefly summarized as : "less disturbance, early spray anchor, ground measurements, closed tight."3．With a spring to understand the principle NATM（1）. Cavern brink of a point A in the original excavation ago with stress (stress self-respect and tectonic stress) in a state of equilibrium. As an elastic stiffness of the spring K, P0 under compression in a state of equilibrium.（2）. Cavern excavation, A point in attacking lose face constraints, the original stress state to be adjusted, if the intensity of rock big enough, After less stress adjustments maycavern in a stable condition (without support). But most of the geological conditions of the poor, that is, after the stress cavern adjustments, such as weak protection, we could have convergence deformation, even instability (landslides), must be provided to support power PE, in order to prevent landslides instability. Equivalent to the Spring of deformation u, in the role of PE is now in the midst of a state of equilibrium.（3）. By the mechanical balance equation, we can see in the spring P0 role in a state of equilibrium; Spring in the event of deformation u, PE in the role they will be in equilibrium, assuming spring elasticity of K, were : P0=PE+KuDiscussion :(1) When u = 0, that is not allowed P0=PE rock deformation, is a rigid support, not economic;(2) when u ↑, PE ↓; When u ↓, PE ↑. That is, rock deformation occurred, the release of some of the load (unloading), we should allow some extent rock deformation, to give full play to rock the capacity for self. Is an economic support measures, the rock self-stability P=P0-PE=Ku;(3) When u=umax, landslides, have relaxation load and unsafe.4. Points（1）. Rock cavern excavation is affected by that part of rock (soil) body, the rock is a trinity : have a load bearing structure, building materials.（2）. Tunnel construction is in the rock stress is of special architectural environment, which can not be equated with the construction on the ground.（3）. Tunnel structure rock + = bracing system.II. The new Austrian highway construction in the basic methodNATM one of the characteristics is the scene monitoring, measurement information to guide construction, through the tunnel construction measure receipts and excavation of the geological observation for prediction and feedback. And in accordance with the established benchmark for measuring the tunnel construction, excavation section steps and sequences, Supporting the initial parameters for reasonable adjustments to guarantee the safety of construction, a tunnel rock stability, the quality of the project and supporting structure of theeconomy and so on. The author of commitments (Chengde) Chek (Chifeng) East Maojingba Tunnel NATM basic construction method for investigation concluded, synthesis of a new highway tunnel Natm the selection of different types and the basic characteristics of the construction methods and tips.1. A tunnel construction method of choice tunnel construction method of choice, mainly based on the engineering geological and hydrogeological conditions Construction, rock type, buried deep tunnel, the tunnel section size and length lining types, Construction should be the premise of safety and engineering quality at the core, and with the use of the tunnel function, the level of construction technology, Construction machinery and equipment, time requirements and economic feasibility of factors to consider in selection.When choosing the method for tunnel construction on the surrounding environment negatively affected, should also be a tunnel, the environmental conditions as the method to choose one of the factors, taking into rock changes the method and the applicability of the possibility of change. Tunnel project to avoid mistakes and unnecessary increase investment in public works. NATM new construction, we should also consider the entire process of construction of auxiliary operations and changes in the surrounding rock to measure control methods and the tunnel through special geological lots of construction means for a reasonable choice.2. New Austrian Tunneling Method program New Austrian Tunneling Method used all methods can be divided into sections, Division level and the three major types of excavation method and some changes in the program.(1) Full-face method. That whole section excavation method is based on the design of an excavation face excavation molding. Excavation order is its full face excavation, steel bracing, pouring concrete lining. Often choose to IV-VI Class Rock Hard Rock Tunnel, which can be used blasting deep hole.Excavation whole section of the law is a larger space operations, introducing supporting large mechanized operations, improving the speed and process small, less interference and facilitate the construction organization and management. Excavation is due to shortcomings in the larger, lower relative stability of rock, and with each cycle of the relatively large workload, it requires the construction units should have a strong excavation, transport and slag out andsupport capability, Maojingba VI : Class V rock used in the full-face excavation to achieve the desired results.Full-face excavation face, drilling and blasting construction more efficient use of deep focus to accelerate the excavation blasting speed, and the rock blasting vibration frequency less conducive to a stable transfer rocks. The drawback is every deep hole blasting vibration larger. Therefore require careful drilling and blasting design and strict control of blasting operations.Full-face excavation method is the main process : the use of mobile carts (or platforms), the first full-face a bored, and installed a line, and then drilling platform car outside 50m back to a safe place and then detonate, Blasting to make a shape out after drilling Jardine car again moved to the excavation face in place, began a cycle of drilling and blasting operations, Anchor sprayed simultaneously supporting or after the first arch wall lining.(2) step method. Step method of design is generally divided into sections on the half-section and the lower half section two excavation molding. Excavation order is its first half excavation arch bolt jet concrete bracing, arch lining, the central part of the second half of excavation, sidewall of excavation, concrete wall jet bolt support and lining. The more applicable to the II, III and soft joint development of the surrounding rock, which were used Tim change program.Long-step method : The next stage distance away, on the general level above 50m ahead, Construction can be assigned to the Department of next larger machine with parallel operations, when mechanical deficiencies can be used interchangeably. When the case of a short tunnel, the upper section will be all dug later, and then dug under the section, the construction of which less interference, single process can work.Short step method : on the stage length 5-50m apply to Ⅱ, Ⅲrock can be shortened Invert closing time, Supporting improve early stress conditions, but larger construction interference, in the event of Soft Rock need to consider carefully, Auxiliary shall be applied measures to stabilize the excavation excavation face, in order to ensure the safety of construction.Ultrashort step method : The only step ahead 3-5m, section closed faster. The method used for the high level of mechanization of various rock section, in the event of the siege softrock when required careful consideration. Auxiliary shall be applied measures to stabilize the construction excavation face to ensure the safety of construction.Excavation level of character is the first step to using light excavation drilling machine drill a hole, rather than through large drilling platform car. Two step method of excavation operations with sufficient space and a faster rate of construction. Level is conducive to the stability of excavation face. Especially Excavation in the upper, lower operational safety. Three step method of excavation is the next shortcomings of operations interfere with each other. It should be noted at the bottom of the upper operational stability, level of excavation will increase the number of country rock.(3) Segment excavation method. Excavation Law Division can be divided into five changes in the program : Excavation Division level, from top to bottom hole lead, heading advance on the excavation, single (double) and lateral pit method. Excavation will be conducted Section Division excavation by the Ministry of shape, and to advance some of excavation, it may be called derivative ahead excavation pit method.Law Division level : general application or soil collapse easily lots of soft rock, with its advantages - stage method, height can be lengthened, the two-lane tunnel for a hole-fold, cycling Road Tunnel - hole 2 times; rather than single (double) PENDANTS Heading a high degree of mechanization, can accelerate the progress of the projects.The next heading advance excavation method (that is guided pit wall first arch) : This Act applies to Ⅱ, Ⅲrock. in the soft ground tunneling, to be adopted next general guide advance excavation pit wall first arch Act. Its advantages are : Heading advance excavation, the use of proven geological conditions in advance to facilitate change in the method. Face to facilitate started procedures applicable to the labor arrangements for the use of small machinery and construction. The drawbacks : The next section will guide small, slow construction and construction processes more, construction and management difficult.Unilateral-arm pit Law : rock instability, the tunnel span larger, ground subsidence is difficult to control when using this method. Its characteristics are : a positive step and arms Heading Act advantages.Bilateral arm Heading law : in large-span shallow tunnels, surface subsidence require strict, especially poor rock used. Advantages of this method are : Construction of safe, reliable, but slow construction, high cost.III.The main tunnel construction technology1. Cave construction（1）excavation slope aroundLofting total station measurements, the use of excavators from top to bottom, paragraph by paragraph excavation, not the amount of excavation or the end of next overlapping excavation, remove pits with the above may slump topsoil, shrubs and rock slopes, rock strata of slope excavation needs blasting, Discussion should focus mainly loose blasting. Also partial artificial finishing, when excavation and inspection slope of slope, if sliding and cracking phenomenon and slowing down due slope.（2）.Cheng Tung-supportingYang Brush Singapore Singapore after the completion of timely inspection plate slope gradient, the gradient to pass the inspection, the system set up to fight time anchor, and the exposed bolt heads, hanging metal based network expansion and bolt welding into first overall. Linked network immediately after the completion of shotcrete and repeatedly jet until it reaches the thickness of the design so far.（3）.as of gutter constructionYang slope away from the groove 5 meters excavation ditch interception, interception gutter mainly mechanical excavation, artificial finishing, after dressing, 7.5# immediately masonry made of mortar and stones, and the floor surface with mortar.2. Auxiliary construction（1）A long pipe roofSets arch construction : construction Lofting, template installation, assembling reinforcement, the guidance of lofting 127 installation guide, concrete pouring.Pipe specifications : Heat Nazarbayev Seamless Steel Tube ￠108 mm and a thickness of 6 mm, length of 3 m, 6 m;N pipe from : Central to the distance 50 cm;N Inclination : Elevation 1 ° (the actual construction works by 2 °), the direction parallel with the Central Line;N pipe construction error : Radial not more than 20 cm;N tunnel longitudinal joints within the same section with more than 50% adjacent pipe joints staggered at least a meter.A. pipe roof construction methodLofting accurate measurement personnel, marking the centerline and the vault out of its hole elevation, soil excavation reserved as a core pipe roof construction work platform Excavation footage of 2.5 meters, after the end of excavation, artificial symmetrical on both sides of excavation (Commodities H) platform, level width of 1.5 meters, 2.0 meters high, as construction sets and pipe arch shed facilities drilling platform. Pipe-roof design position should be and it should be a good hole steel tube, grouting after playing non-porous tube steel, non-porous tube can be used as pipe inspection, Grouting quality inspection, drill vertical direction must be accurately controlled to guarantee the opening hole to the right, End each drilling a hole is a pipe jacking, drilling should always use dipcompass drilling pipe measuring the deflection, found that the deflection over design requirements in a timely fashion. Pipe joints using screw connection, screw length 15 cm, to stagger the pipe joints, odd-numbered as the first section of the introduction of three-meter steel pipes and even numbered the first section of pipe using 6 meters, After each have adopted six-meter-long steel pipe.B. pipe roof construction machineryN drilling machinery : XY-28-300 equipped with electric drill, drilling and pipe jacking long shelf;N grouting machine : BW-250/50-injection pump two Taiwan;N using cement-water glass slurry. Mud and water volume ratio 1:0.5; water glass slurry concentration of water-cement ratio 1:1 silicate 35 Baume; The efficacy silicate modulus pressure grouting pressure early pressure 2.0MPA 0.5~1.0MPA; end.（2）. a small catheterA. small catheter used ahead diameter of 42 mm and a thickness of 3.5 mm thermal Nazarbayev seamless steel tubes, steel pipe was front-tip, Welding on the tail ￠6 stiffening brace and the wall around the drilling hole grouting 8 mm, but the tail of a meter without grouting holes and Advance Construction of a small catheter, the tubes and the lining of the centerline parallel to 10 ° -30 ° Chalu into the rock arch. penstocks to 20-50 cm spacing. Each was over a steel tubes, should be closed immediately shotcrete excavation face and thengrouting. After grouting, erecting steel Arch, Supporting the early completion of every (2-3 meters, and the paper attempts to be) another one for steel tubes, Advance small catheter general lap length of 1.0 meters.B. Grouting parametersN water slurry and water glass volume : 1:0.5;N slurry water-cement ratio 1:1N 35 Baume concentration of sodium silicate; The efficacy silicate modulusN grouting pressure 0.5~1.0MPA; if necessary, set up only orifice Pulp Cypriots.（3）. bolting ahead : The Chalu must be greater than 14 degrees, grouting satiated and lap length is not less than 1 meter.3.Correcting constructionEmbedded parts used by the Design Dimensions plank make shape design, installation in contrast snoop plate car, and position accuracy (error ± 50CM), the firm shall not be fixed, you must be in possession of the wire through the middle wear.4. Leveling ConstructionInstallation templates, at the request of both sides leveling layer calibration position to install template. Side-channel steel templates used [10#, top elevation with a corresponding length of the road elevation unanimously to allow deviation ±2mm. adjusted using the standard measurement to determine elevation. Every template fixed a certain distance from the outside to ensure that no displacement, the joints template close comfort, not from a slit, crooked and formation, and the bottom connector templates are not allowed to leak plasma. Concrete before reperfusion, the bottom surface of concrete must be clean. When the concrete arrived at the construction site directly installed backward mode of the road bed, and using artificial Huabu uniform. Concrete paver should be considered after the earthquake destroyed the settlement. Unrealistically high can be 10% higher, Lan is the surface elevation and design line. Concrete earthquake destroyed at or anywhere near the corner with plug-Lan Lan pound for pound order; Flat-Lan pound for pound crisscross comprehensive Lan, Inside each location is no longer the time for concrete sinks, no longer emitted large bubbles, and the surface of cement mortar later. normally no less than 15 seconds, also should not be too long;Then Chun-pound beam along the longitudinal Lan-pound trailer, With redundant Chun-pound concrete beams were dragged shift Trim, Dixian Department should keep leveling Lan facts. Finally, the diameter 75~100mm rolling seamless steel pipe for further leveling. Just do prohibited in the surface spraying water, and threw cement.5. Water, cable duct constructionInstall groove wall reinforcement of location accuracy, the line must be linked to the construction. Install groove wall purity, the purity requirements of accurate location, a vertical line. Dyadic greatest degree of not more than 3 mm, and template-Ditch The top-pronged, pass the inspection before the concrete reperfusion, on the side of the original wall must pick hair, and embedded parts to the location accurately. Template using stereotypes purity.6.Gate ConstructionCleared the site for construction layout. By design size requirement dug-wall basis. M7.5# masonry made of mortar and stones.Template installation, location accuracy requirements purity, a vertical line, and timely inspection template slope. Concrete pouring 15 # Riprap concrete, concrete strength to be more than 70% for Myeongdong vault backfill.Myungdong vault backfill should hierarchical compaction said. The typical thickness of less than 0.3M, both backfill surface height difference of not more than 0.5M. restored to the vault after the pack to design hierarchical compaction high, the use of machines rolling, Ramming must manually filled to vault over 1.0M before mechanical compaction .7 .Construction safety and environmental controlEntrance to wear helmets to prevent crashes, in which the speed limit 5KM, lighting must be a 10-meter lights reckless goods stored material must be standardized and distributed under special guard.Spoil venues must be smooth drainage, and must be masonry retaining wall to prevent flooding, debris flow forming.8. The construction process has to tackle the problemsConstruction of two liner after water seepage treatment :Small cracks with acrylic, water or slurry coating of epoxy resin and other caulking, a good effect; On the larger cracks, available on the 10th of cement mortar or cement mortar expansion caulking more appropriate and effective;Large cracks (crack width greater than 5MM), (if leakage of water, available along the cutting machine cutting a wide cracks around 2~4CM small groove depth approximately 10CM above the water, Cutting a 5 × 5CM Cube holes room, then insert a pipe 4 × 4CM MF7 plastic Blind groove, Cutting together into good pressure tank, the introduction of vertical water drains, Finally, cement and water Glass closed mixed mortar cutting groove) without seepage, it is appropriate epoxy mortar, or grouting, Reinforced concrete and other reinforced jet.IV. Example projectsNATM is from the introduction of the bolt and shotcrete a category of "active" support the new technology to promote the use began. Soon, the Chinese engineer on the tunnel not only in substance but also in terms of acceptance of the new Austrian law. To be held in China in the tunnel and underground engineering academic meeting, the new Austrian capital has become a hot topic.Engineers of the new Austrian law relishes is justified : the use of new Austrian law, has been successful in soft rock and difficult conditions of the construction of various types of underground works.Built on loose sand gravel stratum of Beijing Subway allowed back of the tunnel is a typical example. The tunnel is located in the main street-256, 358m long, the largest excavation section 9m high, 14.5m wide coverage stratigraphic top of the tunnel only minimum thickness 9.0m. Tunnel boring machine of excavation, strengthen the grid arch shotcrete initial support and advance small catheter care, Without prejudice to ground transportation, underground pipelines to ensure the safety of construction success.In the works is the experience, knowledge of the Chinese engineers, the use of new Austrian law principles can be used in the Mountain Tunnel Mine Act to expand the scope ofapplication of the soft rock, even in the fourth strata of municipal shallow tunnel to replace the traditional method of digging or shield. In China, such a method called "shallow mining method."Following allowed back lane tunnel, gravel in the same folder of alluvial gravel layer is shallow mining method used to build the span of 21.67m in the Xidan MTR stations.Changan Avenue in the construction of the new Beijing metro line projects, shallow mining method has been selected as the main method of construction. For example, the Tiananmen Square in Beijing Metro West Point, 226m long, for two double-pole structure.Guangzhou Metro East is shallow mining method used in the construction. Experience shows that from the ground environmental protection, surface subsidence of the dug system and the cost and time period perspective, Shallow Mining Act of open or with the shield are compared with a competitive edge.Chinese engineers from Europe to the introduction of the new Austrian law, and in light of China's situation of the new Austrian law, and related technology expanding means of support, such as, measurement and control technology was further developed. As a new Austrian law an important background shotcrete technology in China has been widely used. With the international situation, in order to resolve the long-troubled people of dust pollution of the environment. Rebound serious and concrete uneven quality of such issues, and is vigorously implementing the wet spray. Recently by the China Academy of Railway Sciences Southwest Branch of the development of a "Rotor-Piston," a new type of jet aircraft. This type wet spraying process, which is to include the machines Mix Concrete Preparation good product mixture, However, material handling is different from the general-pumping wet spraying machine, using thin stream conveyor. Therefore machines compact and easy to use. Has been popularized in this country.It is no exaggeration to say that the new Austrian law implementation has indeed caused a mining method in the construction of the excavation, Construction of the tunnel design, and even the thinking of the major changes. Nevertheless, it should be said that China's implementation of the new Austrian law is not satisfactory. In many works was no lack of examples of failure. In addition to construction management, quality control and technology related to grasp, and other reasons, is the main tunnel engineers sometimes NATM real lack of a proper understanding.。

Tunnelling by Tunnel Boring Machine (TBM)Authors : P N Kessler, Executive General Manager, Transfield Tunnelling and C J Moore, Mechanical Engineer, Transfield Tunnelling, Australia.1 Introduction1.1 First Concept of TBM Tunnelling, Channel Tunnel 1880’sWell before expanding urban sprawls and choking traffic congestion forced us to seriously look at underground construction, some people thought it would be easier to go under instead of over. Many technical challenges beset those who embarked on this course. It has taken some 200 years for construction techniques and tunnelling plant development to deliver reliable solutions to today’s tunnellers, not the least of which is the modern day Tunnel Boring Machine.It is claimed that the first attempt to drive a tunnel with a TBM was with the use of two Beaumont-English steam powdered 7 feet (2.13 metres) machines from 1881 to 1882.This was a brave attempt to build a tunnel for horse and carriage traffic across the English Channel. The Miners of the day reached an impressive 1,883 metres from the English side and 1,663 metres from the French side before the British parliament withdrew their backing and money due to lack of public support. It was rumoured that in fact the British drive was halted due to fears that a completed tunnel could be used as a means of French invasion.It would take a further 115 years or so before the feat was achieved and with the best planning and modern technology that could be supplied at the time.1.2 Robbins Machine 1951After the first endeavours with a Tunnel Boring Machine by the English several decades passed before Dick Robbins of the Robbins Company in the United States, developed and manufactured the first commercially available Hard Rock Tunnel Boring Machine in 1951. Machines of today still have the basic design concept, consisting of a rotating cutterhead mounted on a main beam or kelly with gripper pads that thrust off the tunnel wall to drive the machine forward. Since then Shielded, Double Shielded, Slurry and Earth Pressure Balance EPB Tunnel Boring Machines have been developed by a number of companies to drive tunnels in all manner of ground conditions.2 Today’s TBM family of machinesThe following table outlines the typical family of TBMs and the ground they are designed to traverse.Machine Type Typical MachineDiameters Best suited for the following groundconditionPipe Jacking Machines Up to approximately 3to 4 metresAny groundSmall Bore Unit(SBU)Up to 2.0 metres Any groundShielded TBMs 2 to 14 metres plus Soft Ground above the water tableMix Face TBMs 2 to 14 metres plus Mixed ground above the water tableSlurry TBMs 2 to 14 metres plus Coarse gained soft ground below the watertableEPB TBMs 2 to 14 metres plus Fine grained soft ground below the water table Hard Rock TBMs 2 to 14 metres plus Hard rockReamer TBMs Various Hard rockMultihead TBMs Various VariousFig 2- Multi head TBM.Fig 3 - EPB Machine.Fig 4 - Mix Shield Slurry Machine – Hong Kong 5.1 metres.Fig 5 - Double Shielded Machine.Fig 6 - Hard Rock Machine Open Beam Machine.Fig 7 - Slurry Machine (Channel Tunnel - France, 8.8 metres).Fig 8 - Hard Rock machine Kelly Type (Northside Storage Tunnel – Australia, 6.56 metres).The remainder of this paper will concentrate on Hard Rock TBMs for medium to large diameter Tunnels. It will also address the machine requirements to deal with ground water inflows and the possible need for pre excavation grouting or ground treatment, in order to make the project an economic and construction success.3 Basic Hard Rock TBM DesignThe mechanism by which a hard rock TBM excavates is by cutting the rock with roller disk cutters. The rock failure is actually by shear that occurs due to the penetration of the cutter tip into the face. The cutters are manufactured with hardened tool steel and range in size of typically 12 to 19 inches in diameter. The cutters are mounted on the cutterhead in a pattern and number that will provide coverage over the entire face.The above two diagrams are typical cutter patterns for a machine of approximately 7 metres diameter.The pattern design and number differs for one manufacture to another.There are three main types of cutters, centre, face and gauge. The centre and face cutters are positioned to excavate the bulk of the face. The gauge cutters are mounted on the perimeter of the head and, as their name implies, cut the gauge or final diameter of the tunnel.As the rock is sheared or cut it falls to the invert, where muck buckets scoop the material into the head. As the bucket raise to the top, with the rotation of the head, it falls into a muck hopper. From here it is discharged onto a conveyor belt that is mounted either on top of or inside the main beam, which takes the spoil to the rear of the TBM. From here a series of conveyors then transports the spoil across the bridging structure and along the backup. Disposal of the spoil from the backup can be via a number of means including additional conveyors or muck cars.The TBM is propelled forward off grippers. These grippers are hydraulically jacked against the tunnel wall. Hydraulic cylinders between the gripper assembly and the main beam are used to push the main beam and hence the cutterhead forward. The thrust length or stroke is determined by the length of the thrust cylinder, which is typically 1.2 to 1.8 metres. At the completion of the stroke, front and rear stabilising legs are lowered to support the machine. The grippers are retracted off the wall and the thrust cylinders are used in reverse to move the gripper forward on the main beam. The grippers are then extended to grip the wall and the stabilising legs raised. The excavation then continues for another stroke.Thrust CylindersFinger Shield GrippersTBM Back UpConveyorRoof BolterWalking Frame – removedfrom machine when boringTunnelCutterhead & ShieldFig 11.The forces with which the TBM grips and thrusts and the torque which the cutterhead develops will vary from machine to machine and moreover on cutterhead diameter. Typically a hard rock machine of about 7.0 metres in diameter, will have specifications in the following ranges:Installed cutter motor power: 2,100 to 3,400 kW.Max cutterhead torque: 2,500 to 5,200 kNm.Thrust:12,000to18,500kN.Gripper force is in the order of twice the thrusting capacity.4 Drivers for TBM selection for Hard Rock conditionsThe criteria that will govern TBM selection in hard rock conditions will be mainly influenced by the geology of the rock mass to be encountered. The variation of this geology over the entire length of the tunnel will govern how versatile the machine needs to be or how easily it can be modified to best adjust to the differing conditions. Issues that need to be addressed for machine selection and type of supporting or ancillary equipment required include:• Using tunnelling methods as opposed to trenching or cut and cover construction. For modern high density cities, the disruption to structures, services and people using the sometimes cheaper top-down construction methods can in the long run be more expensive than using tunnelling technology. While tunnelling is more expensive in the construction sense, savings are made in the non-disturbance to the public and the neighbourhood.• Final support or finishing requirements of the tunnel (eg, segmentally lined, cast insitu concrete lining, shotcrete or bare rock). This will govern where the lining is installed either as part of the excavation phase on the TBM, as a secondary activity behind the machine or after excavation is complete.• Temporary support requirements and its design (eg steel sets, rockbolts, cable anchors, mesh and strapping or shotcrete). The allowed ‘hang time’ of the rock will drive how far from the cut face the support will need to be installed. Design issues with respect to bolting or anchor diameters and lengths or shotcrete thicknesses will also play a major role in ancillary equipment selection and location on the TBM or Backup Train. Steel set sizing and spacing will need to be designed and selected to allow the TBMs grippers to set around them or in between them as the machine advances.• The variation of the Geology or the expectation of meeting complicated or difficult geological features may require the ability to probe drill. The orientation and extent ofthese features will determine the probing envelope that will be required with respect to depth of hole and orientation to the cutterhead (ie through the head, over the head or completely around the head).• The expectation of ground water being encountered plays a major role in equipmentselection. Primarily the amount of inflowing ground water that can be tolerated during construction and the allowed total inflow after tunnel completion will govern the type of ground water control. This can include the requirement for either ground treatment or membrane lining installation or drained tunnel techniques and the associated water draining methods that must be adopted in the lining and or invert drainage system.• The tunnel alignment with respect to horizontal curves and vertical gradients willgovern the TBMs cutting and re-gripping dynamics and muck haulage system. Tight horizontal curves may influence stroke length and gripper orientation. A single gripper system allows steering or heading adjustments of the machine during the stroke. Machines with multiple sets of grippers excavate straight sections of tunnel during the stroke followed by heading adjustments during the re-grip. Steep gradients may negate the possibility of a rolling stock muck handling system and require a continuous conveyor type system.When the above issues are addressed, and there quite possibly will be others, the TBM overall configuration will become much clearer. TBM suppliers can then be approached with a specification for the type of machine and the ancillary equipment required to address the job. This may then indicate if a refurbished machine is available or whether a new machine will need to be manufactured. The TBM and backup will probably be the major plant expenditure on the project and hence investigation of available machines and configurations available must be thoroughly examined.5Overcoming challenges during Tunnelling5.1 Materials HandlingMaterials handling is a major influence on TBM production and advance rates. The TBM can only go as fast as the mucking system can remove excavated spoil. There are a number of techniques for spoil handling. They include haulage by rolling stock, continuous conveyor or by hydraulic means (ie slurry). As mentioned before gradients may make muck handling an easy decision with respect to rolling stock. Primarily it will come down to operational flexibility, capital expenditure and operational costs. The major advantages and disadvantages are as follows:Technic Advantages Disadvantages Conveyor • Can be designed for almost all production rates• Keeps tunnel clear for other activities such as man and materials haulage or secondary construction activities in the tunnel.• Needs low manpowerrequirements usually only maintenance personnel.• Running costs is usually the cheapest of all the methods.• Tight horizontal bends may limitits capacity or viability. High capital cost may be incurred to cater for it. Ongoing maintenance and tracking problems can also be a factor on its availability. This in turn affects TBM excavation rates. • When the conveyor is down the TBM is down.• Maintenance cost can be high with respect to wear items such as rollers and belt.• Can be used on all gradients from flat to vertical. Thesteeper the gradient however,the greater the capital andrunning costs.•Capitals cost can be prohibitive but becomes more cost effective than the other methods as the drive gets longer. Some consultants will argue it is the most cost-effective method with drive lengths over 4 kilometres. Rolling Stock • The system is flexible in that multiple trains and can be usedand sized for differingproduction rates of the TBM.• A single train breakdown mayonly slow TBM production notstop it due to having extra or back up rolling stock.• The rolling stock can be used toperform others duties such as materials and man haulage.Dedicated trains for thispurpose can be kept to aminimum. • Downtime is generally lowerthan the other methods. Itrequires no programmed stoppage such as booster driveinstallation for conveyors andpipes installation for the slurrysystem.•Is more labour intensive than the other systems in that it not only needs dedicated maintenance personnel but also requires operators for each train and at the feed points and discharge points. •If the TBM maximum production is high then the size of the rake becomes large. •If tunnel drives are long the number of trains required will increase causing it to be an expensive capital expenditure. •When muck hauling is occurring it will dictate the tunnel activities behind the TBM. • Can not be used on steep gradients (>4%). Slurry or Hydraulic means • Can generally be sized for any TBM production rates.• Is the most economical when itcomes to area required alongthe tunnel length. Only a supply and a discharge line is required.• Downtime is usually very low but when the system failsstoppages can be excessive.• It can be used on all types of gradients. •Will probably require a crusher unit on the TBM in order to reduce the size of the aggregate to an acceptable pumpable size. •It is usually the most expensive of all methods in capital costs. •The slurry will require secondary treatment to remove the hydraulic medium from the spoil. •It tends to have the highest running costs, this system will be quitepower hungry.The selection of the correct materials handling system can only be made after addressing all issues with respect to tunnel configuration and length.5.2 Excessively Hard Rock (+150MPa UCS)Encountering excessively hard rock will have a bearing on the number, type and size of cutters required. Each cutter will have a maximum thrust loading which it can endure, generally limited by the cutters bearing capacity. Modern high performance TBM’s (HP TBM’s) are usually fitted with larger diameter cutters which allow the use of bearings designed to withstand the higher loadings required to penetrate harder rock. Cutter diameters have increased as technology has improved and HP TBM’s are now using 17”, 19” and, in limited numbers, 21” rings. This increase in diameter also increases thevolume of available wear material on the cutter ring which decreases the frequency of cutter changes required.The cutter kerf spacing is generally reduced slightly resulting in a larger number of cutters on the face. The greater the number of cutters, the greater the cutting thrust that can be exerted on the face. The TBM must have the available thrust capacity to cater for this. The higher the thrust the greater the penetration rate and hence the greater the advance rate. Insufficient thrust will cause low advance rates and excessive cutter wear in hard rock. This in turn requires more frequent maintenance stoppages and a greater number of cutters to be changed. As a result cutter consumable costs will be higher and TBM availability will be lower. It is therefore important to match cutter selection and machine capability to the rock strengths likely to be encountered to ensure optimum cost efficiency.Fi 12 - The cut face.5.3 Wet Tunnelling ConditionsWet conditions can be the most difficult conditions to cater for on a TBM. While large volumes of water can be a nightmare, the presence of even a modest amount of water through the face or from the crown can be a problem.If the excavation is proceeding on a downhill gradient it is imperative to have an adequate dewatering system on the TBM and along the tunnel length. The presence of invert water at the face will invariably affect TBM production from machinery availability to the morale and productivity of the TBM crew. It is also highly advisable that an emergency pumping and power system is available in case of equipment or power failure. Recovery of a flooded TBM can be expensive and time consuming.The possibility of water ingress through the face and the crown will have a bearing on ancillary equipment selection and set up. The best dust extraction system on a TBM is a dry bag type but these will not tolerate the ingestion of water. Primarily the extraction system draws directly from the cutterhead. Water through the face can be sucked into the inlet duct of the extractor. In these conditions a water interceptor (which may not be every effective) can be installed or a wet type scrubber should be used. Wet type scrubbers are not as efficient in removing dust as the dry bag type but when water is flowing from the face dust production is usually quite low. The other solution is to turn off the dry bag extractor while cutting in wet ground. This will affect the airflow around the machine and extra ancillary fans and air quality testing should be carried to ensure condition meet OHS standards.Electrical equipment is also susceptible to the presence of water. Free water from the rock face will also increase the humidity of the air. It is therefore important that all electrical equipment has the appropriate protection rating. Air heaters or dryers can be adopted in substations and switchboards to alleviate this problem. Wherever possible hydraulically operated equipment should be used instead of electrically operated. For example most drilling and bolting rigs are driven hydraulically but can be controlled electrically or hydraulically. It is highly recommended that these rigs be hydraulically operated. Electrically operated drilling rigs in wet conditions are susceptible to higher amounts of down time.In most tunnelling applications water cannot be tolerated in large volumes for the final tunnel product. Therefore the ingress of ground water must be limited, which can be done pre or post excavation. Pre-excavation ground treatment will slow TBM production but is usually more effective than post excavation treatment. It is far more difficult to achieve good results using post excavation treatment as many features can be more easily and economically treated when confined ahead of the TBM than when completely exposed in the tunnel bore.When pre-excavation grouting is to be adopted it is important to recognise what area or volume of ground needs to be treated and where it is with respect to the cut face. Probe holes will be required to be drilled, to establish water bearing feature locations and their flow rates and pressures. Selection of the drilling rigs and their configuration should be sourced to reach these features and effectively treat the area around them. This may require drilling holes out past the cutterhead and possibly 360o around it. The angle at which the rig can drill a hole into the tunnel wall will govern how far into the rock the treatment can be injected. The usual set up for these drills in on a rack and pinion arrangement that circles in the plane perpendicular to the main beam of the TBM. The drill is mounted on this rack facing towards the cutterhead. It can then be angled back to drill into the tunnel wall. The greater the angle the deeper into the wall it will penetrate as it drills forward.Fig 13 – Typical cone of coverage for forward probing and ground treatment.Usually it is advantageous to intercept the water feature in front of the cutterhead well before the excavation reaches it. This will minimise the possibility of the water finding a path through the tunnel wall behind the face. If the TBM excavation is directly through a water feature (ie it is above, below and around the excavation) the ground treatment will need to be carried out right around the cutterhead and in front of it. In effect a cone of treated ground must be formed before the TBM can excavate through it. This may not eliminate water flow through the centre of the cone and through the cut face. It may therefore be necessary to have the ability to drill through the cutterhead in order to form a plug of treated ground in front of the TBM. Cutterheads with the appropriate portholes positioned in them are available for such applications. This however can be difficult on TBMs of less than four metres diameter. The gear assembly, main bearing or drive motors mounted on the rear of the cutterhead does not allow enough space for potholes to be located. In fact machines with cutterhead motors mounted to the rear of the TBM body, with drive shaft through the main beam to the head, are the most conducive to modifying for through the head drilling.Once the ground in front of the TBM has been treated, it can excavate through a block of now water-resistant ground. The TBM may have to be stopped and the ground forward of the machine treated again before excavation can continue. This treating of the ground and excavation cycle will continue until the water feature is passed. It must be noted however that drilling through the head does carry some risk. The loss of a drill string in front of the head will slow progress while excavating. TBM’s are designed to cut rock not drill steels. The drill steel when hit will only bend away and damage cutters. The excavation will need to proceed slowly, exposing the drill steels and removing them by oxy-acetylene cutting a bit at a time. This must continue until the entire string is recovered or removed.Good geological investigation prior to excavation will be required to determine the type of ground treatment medium to be used. This can range from normal grout mixes with general purpose, super-fine and micro-fine cement to polymer type grout products. Once this has be determined the appropriate grout pump equipment can be source, which can also be incorporated into the backup train configuration.5.4 Capacity to deal with changing Support ConditionsIt is common for a TBM to need the ability to install various methods of ground support. Typically in hard rock this can range from a simple rockbolt pattern to closely spaced sets and possibly shotcrete. The pre-excavation geological investigation should outline all foreseeable support criteria. Twin roof bolters are usually mounted on either side of the main beam or kelly behind the cutterhead. They will drill holes and insert bolts through a finger shield mounted off the rear of the cutterhead shield. It is important to insert rockbolts as close to the cut face as possible. This is to ensure the rockbolt can perform it task prior to the crown relaxing or converging to an extent that it becomes unstable.The kinematics of the bolting rigs must also be considered. This is not so much in the machine selection but in the design of the rockbolt support. Typically the design will be based on fan shaped envelope in the crown (see Fig 14). Because the TBM has a main beam with the bolting rigs mounted either side this perfect pattern is not possible. The below diagram indicates the possible bolt installation profile achievable. On selection of the machine the achievable bolt pattern must then be used to finalise the design of the rockbolt crown support.If sets are required then a set erector will be mounted on the machine. This is also positioned immediately behind the cutterhead. Once again the sets need to be installed as close to the cut face as possible as in the case for rockbolts.Shotcrete may need to be applied either over the rockbolts or to encapsulate the sets.Usually this can be a secondary activity off the backup train or as a totally separate exercise behind the TBM. If shotcrete is required closer to the face, shotcrete booms can be mounted in the bridging structure between the TBM and backup train. Shotcreting off the TBM itself should be avoided where possible due to the damage shotcrete rebound can cause on the TBM and its components. If there is no option then the TBM should be protected as much as possible with plastic sheeting and all exposed hydraulic cylinder rods greased up or covered in tape and plastic. Hand held shotcrete equipment would need to be used in this instance which is very labour intensive.6 ConclusionThe evolution of hard rock TBM’s has rapidly progressed over the last 40 years and further advances in areas such as ground pre-treatment (in-bore and from surface), application of primary and secondary support, materials handling and rate of penetration will continue to challenge tomorrows tunnel engineers. Fundamental to the success of an underground project excavated by mechanical means will continue to be however, the degree to which the geological conditions are anticipated.ReferencesFig 1, Origins unknown.Fig 2, ITA-AITES, Tribune Special Issue, “Why Go Underground”, page 20.Fig 3, Herrenknecht AG, Botelek, “9,755 mm machine”.Fig 4, China Harbour - Transfield Joint Venture, “5.1m Mix Shield Slurry Machine”.Fig , 5, 6,7 & 12, The Robbins Company, various photographs supplied.Fig 8, Northside Storage Tunnel Alliance, “6.56m TBM”.Fig 9, Wirth GmbH, Part of drawing A3008652, “TB 563 E TBM Zusammenstellung”.Fig 10, Herrenknecht AG, Part of drawing A-1432-50, “ TUNNELLINGSYSTEM Gripper ø 6800MM”.All other figures and diagrams produced by Transfield Tunnelling.。

隧道工程相关专业英语词汇隧道 tunnel●隧道工程 tunnel engineering●铁道隧道 railway tunnel●公路隧道 highway tunnel●地铁隧道 subway tunnel ; underground railway tunnel;metro tunnel●人行隧道 pedestrian tunnel●水工隧洞 ;输水隧道 hydraulic tunnel●山岭隧道 mountain tunnel●水下隧道 subaqueous tunnel●海底隧道 ;水下隧道 submarine tunnel;underwater tunnel●土质隧道 earth tunnel●岩石隧道 rock tunnel●浅埋隧道 shallow tunnel;shallow-depth tunnel ;shallow burying tunnel●深埋隧道 deep tunnel;deep-depth tunnel ; deep burying tunnel ●偏压隧道 unsymmetrical loading tunnel●马蹄形隧道 ;拱形隧道 horse-shoe tunnel ; arch tunnel●圆形隧道 circular tunnel●矩形隧道 rectangular section tunnel●大断面隧道 largecross-section tunnel●长隧道 long tunnel●双线隧道 twin-track tunnel ; double track tunnel●曲线隧道 curved tunnel●明洞 open tunnel;open cut tunnel;tunnel without cover;gallery隧道施工方法 tunnel construction method●钻爆法 drilling and blasting method●新奥法 natm;new austrian tunnelling method●盾构法 shield driving method;shield method●顶进法 pipe jacking method ; jack-in method●浅埋暗挖法 sallow buried-tunnelling method●明挖法 cut and cover tunneling;open cut method●地下连续墙法 underground diaphragm wall method;underground wall method●冻结法 freezing method●沉埋法 immersed tube method●管棚法 pipe-shed method隧道勘测 tunnel survey●超前探测 drift boring●工程地质勘测 ;工程地质勘探 engineering geological prospecting●隧道测量 tunnel survey●施工测量 construction survey●断面测量 section survey●隧道设计 tunnel design●隧道断面 tunnel section●安全系数 safety coefficient●隧道力学 tunnel mechanics●隧道结构 tunnel structure ●隧道洞口设施 facilities of tunnel portal●边墙 side wall●拱顶 arch crown●拱圈 tunnel arch●仰拱 inverted arch●底板 base plate;floor●隧道埋深 depth of tunnel●隧道群 tunnel group●隧道施工 tunnel construction●隧道开挖 tunnel excavation●分部开挖 partial excavation●大断面开挖 large cross-section excavation●全断面开挖 full face tunnelling●开挖面 excavated surface围岩压力 ground pressure;●surrounding rock pressure●围岩变形 surrounding rock deformation●围岩破坏 surrounding rock failure●软弱围岩 weak surrounding rock支护 support●锚喷支护 anchor bolt-spray support●锚杆支护 anchor bolt-support;anchor bolt support ●喷射混凝土支护 ;喷射砼支护 shotcrete support;sprayed concrete support●配筋喷射混凝土支护 ;配筋喷射砼支护 reinforced sprayed concrete support●钢架喷射混凝土支护 ;钢架喷射砼支护 rigid-frame shotcrete support●掘进工作面支护 excavation face support●超前支护 advance support●管棚支护 pipe-shed support;pipe roofing support●胶结型锚杆 adhesive anchor bolt●砂浆锚杆 mortar bolt●树脂锚杆 resin anchored bolt●摩擦型锚杆 friction anchor bolt●楔缝式锚杆 slit wedge type rock bolt●涨壳式锚杆 expansion type anchor bolt●机械型锚杆 mechanical anchor bolt●预应力锚杆 prestressed anchor bolt●土层锚杆 soil bolt 岩石锚杆 rock bolt衬砌 lining●整体式衬砌 integral tunnel lining;integral lining●拼装式衬砌 precast lining●组合衬砌 composite lining●挤压混凝土衬砌 shotcrete tunnel lining ;extruding concrete tunnel lining●混凝土衬砌 ;砼衬砌 concrete lining●喷锚衬砌 shotcrete and bolt lining;shotcrete bolt lining隧道通风 tunnel ventilation●施工通风 construction ventilation●运营通风 operation ventilation●机械通风 mechanical ventilation●自然通风 natural ventilation●隧道射流式通风 efflux ventilation for tunnel ;tunnel efflux ventilation;tunnel injector type ventilation●隧道通风帘幕 curtain for tunnel ventilation;ventilation curtain ●通风设备 ventilation equipment隧道照明 tunnel illuminationtunnel lighting照明设备 lighting equipment隧道防水 tunnel waterproofing;waterproofing of tunnel●防水板 waterproofing board;waterproof board;waterproof sheet ●防水材料 waterproof material●隧道排水 tunnel drainage●排水设备 drainage facilites●隧道病害 tunnel defect●衬砌裂损 lining split;●隧道漏水 water leakage of tunnel;tunnel leak●坍方 landslide;slip●地面塌陷 land yielding●涌水 gushing water●隧道养护 tunnel maintenance●堵漏 leaking stoppage●注浆 grouting●化学注浆 chemical grouting●防寒 cold-proof●整治 regulation●限界检查 clearance examination;checking of●clearance;clearance check measurement●隧道管理系统 tunnelling management system●隧道环境 tunnel environment隧道试验 ;隧道实验 tunnel test●试验段 ;实验段 test section●隧道监控量测 ;隧道监控测量 tunnel monitoring measurement ●收敛 convergence●隧道安全 tunnel safety●隧道防火 tunnel fire proofing●火灾 fire hazard●消防 fire fighting●隧道防灾设施 tunnel disaster prevention equipment;tunnel anti-disaster equipment●报警装置 ;报警器 alarming device;warning device●通过隧道 passing tunnel●避车洞 refuge hole●避难洞 ;避车洞 refuge recess;refuge hole电气化铁道工程 ;电气化铁路工程 electrified railway construction●直流电气化铁道 dc electrified railway●交流电气化铁道 ;交流电气化铁路 a.c.electrification railway●低频电气化铁道 low frequency electrified railway●工频电气化铁路 industry frequency electrified railway●电压制 voltage system●电流制 current system。

一、隧道设计施工的两大理论及其发展过程二十世纪以来，人类对地下空间的需求越来越多，因而对地下工程的研究有了一个突飞猛进的发展。

在大量的地下工程实践中，人们普遍认识到，隧道及地下洞室工程，其核心问题，都归结在开挖和支护两个关键工序上。

即如何开挖，才能更有利于洞室的稳定和便于支护：若需支护时，又如何支护才能更有效地保证洞室稳定和便于开挖。

这是隧道及地下工程中两个相互促进又相互制约的问题。

在隧道及地下洞室工程中，围绕着以上核心问题的实践和研究，在不同的时期，人们提出了不同的理论并逐步建立了不同的理论体系，每一种理论体系都包含和解决（或正在研究解决）了从工程认识（概念）、力学原理，工程措施到施工方法（工艺）等一系列工程问题。

一种理论是二十世纪20年代提出的传统的“松弛荷载理论”。

其核心内容是：稳定的岩体有自稳能力，不产生荷载：不稳定的岩体则可能产生坍塌，需要用支护结构予以支撑。

这样，作用在支护结构上的荷载就是围岩在一定范围内由于松弛并可能塌落的岩体重力。

这是一种传统的理论，其代表人物有泰沙基和普氏等人。

它类似于地面工程考虑问题的思想，至今仍被广泛的应用着。

另一种理论是二十世纪50年代提出的现代支护理论，或称“岩承理论”。

其核心内容是：围岩稳定显然是岩体自身有承载自稳能力：不稳定围岩丧失稳定是有一个过程的，如果在这个过程中提供必要的帮助或限制，则围岩仍然能够进入稳定状态。

这种理论体系的代表性人物有拉布西维兹、米勒-菲切尔、芬纳-塔罗勃和卡斯特奈等人。

这是一种比较现代的理论，它已经脱离了地面工程考虑问题的思路，而更接近于地下工程实际，近半个世纪以来已被广泛接受和推广应用，并且表现出了广阔的发展前景。

由以上可以看出，前一种理论更注意结果和对结果的处理：而后一种理论则更注意过程和对过程的控制，即对围岩自承能力的充分利用。

由于有此区别，因而两种理论体系在过程和方法上各自表现出不同的特点。

新奥法是岩承理论在隧道工程实践中的代表方法。

隧道工程英语专业词汇隧道工程tunnel engineering隧道tunnel铁路隧道railway tunnel公路隧道highway tunnel地铁隧道subway tunnel;underground railway tunnel;metro tunnel 人行隧道pedestrian tunnel水工隧洞hydraulic tunnel 输水隧道raulic tunnel山岭隧道mountain tunnel水下隧道subaqueous tunnel海底隧道水下隧道submari netunnel;underwater tunnel 土质隧道earth tunnel岩石隧道rock tunnel浅埋隧道shallow tunnel;shallow-depth tunnel;shallow burying tunnel 深埋隧道deep tunnel;deep-depth tunnel;deep burying tunnel 偏压隧道unsymmetrical loading tunnel马蹄形隧道拱形隧道horse-shoe tunnel;arch tunnel圆形隧道circular tunnel矩形隧道rectangular section tunnel 大断面隧道largecross-section tunnel 长隧道long tunnel双线隧道twin-track tunnel;double track tunnel曲线隧道curved tunnel明洞open tunnel;open cut tunnel;tunnel without cover;gallery隧道勘测tunnel survey超前探测drift boring工程地质勘测工程地质勘探engineering geological prospecting隧道测量tunnel survey施工测量construction survey断面测量section survey隧道设计tunnel design隧道断面tunnel section安全系数safety coefficient隧道力学tunnel mechanics隧道结构tunnel structure隧道洞口设施facilities oftunnel portal 边墙side wall拱顶arch crown拱圈tunnel arch仰拱in verted arch 底板base plate;floor隧道埋深depth of tunnel 隧道群tunnel group 隧道施工tunnel construction隧道开挖tunnel excavation分部开挖partial excavation 大断面开挖large cross-section excavatio n 全断面开挖full face tunnelling 开挖面excavated surface隧道施工方法tunnel construction method 钻爆法drilling and blasting method新奥法natm;new austrian tunnelling method盾构法shield driving method;shield method顶进法pipe jacking method;jack-in method浅埋暗挖法sallow buried-tunnelling method明挖法cut and cover tunneling;open cut method地下连续墙法underground diaphragm wall method;underground wall method:叙吉法freezing method沉埋法immersed tube method管棚法pipe-shed method综合机械化掘进comprehensive mechanized excavation辅助坑道auxiliary adit;service gallery平行坑道parallel adit竖井shaft斜井sloping shaft;inclined shaft 导坑heading衬砌工艺lining process喷锚锚喷anchor bolt spray;anchor bolt-spray管段tube section接缝joint地层加固reinforcing of natural ground弃磴ballast piling施工监控construction monitor control超挖overbreak欠挖underbreak施工进度construction progress隧道贯通tunnel holing-through工期work period隧道施工机械tunnel construction machinery隧道掘进机tunnelling machine;tunnel boring machine;tbm单臂掘进机single cantilever tunnelling machi ne全断面掘进机full face tunnel boring machi ne隧道钻眼爆破机械machine for tunnel drilling and blasting operation 装輕输血loading-conveying ballast equipme nt衬砌扌JIMlining mechanism钢模板steel form模板台车formworking jumbo 混凝土喷射机碇喷射机concrete sprayer前shield泥水盾构slurry shield气压air pressure shield挤压闭胸盾构shotcrete closed shield土压平衡盾构soil pressure balancing shield注浆机械grouting machine凿岩机rock drilling machine;air hammer drill 凿岩台车drill jumbo;rock drilling jumbo围岩surrounding rock围岩分类surrounding rock classificatio n围岩加固surrounding rock consolidatio n围岩稳定surrounding rock stability围岩应力surrounding rock stress围岩压力pressure of surrounding rock 山体压力围岩压力ground pressure;surrounding rock pressure围岩变形surrounding rock deformation围岩破坏surrounding rock failure软弱围岩weak surrounding rock支护support锚喷支护anchor bolt-spray support 锚杆支护anchor bolt-support;anchor bolt support喷射混凝土支护喷射碇支护shotcrete support;sprayed concrete support配筋喷射混凝土支护配筋喷射碇支护reinforced sprayed concrete support钢架喷射混凝土支护钢架喷射碗支护rigid-frame shotcrete support掘进工作面支护excavation face support超前支护advance support管棚支护pipe-shed support;pipe roofing support胶结型锚杆adhesive anchor bolt砂浆锚杆mortar bolt树脂锚杆resin anchored bolt摩擦型锚杆friction anchor bolt楔缝式锚杆slit wedge type rock bolt涨壳式锚杆expansion type anchor bolt机械型锚杆mechanical anchor bolt预应力锚杆prestressed anchor bolt土层锚杆soil bolt岩石锚杆rock bolt衬砌lining整体式衬砌integral tunnel lining;integral lining拼装式衬砌precast lining组合衬砌composite lining挤压混凝土衬砌挤压碇衬砌shotcrete tunnellining;extruding concrete tunnel lining混凝土衬砌碇衬砌concrete lining 喘苗衬砌shotcrete and boltlining;shotcrete bolt lining 隧道通风tunnel ventilation施工通风construction ventilation运营通风operation ventilation机械通风mechanical ventilation自然通风natural ventilation隧道射流式通风隧道射流通风efflux ventilation for tunnel;tunnel efflux ventilation;tunnel injector type ventilation 隧道通风帘幕curtain for tunnel ventilation;ventilation curtain 通风设备ventilation equipment 隧道照明tunnel illumination;tunnel lighti ng照明设备lighting equipment隧道防水Tunnelwaterproofing;waterproofi ng oft unnel防水板waterproofingboard;waterproofboard;waterproof sheet 防水材料waterproof material隧道排水tunnel drainage排水设备drainage facilites隧道病害tunnel defect衬砌裂损lining split;lining **ing隧道漏水water leakage of tunnel;tunnel leak坍方landslide;slip地面塌陷land yielding涌水gushing water隧道养护tunnel maintenance堵漏leaking stoppage注浆grouti ng化学注浆chemical grouting防寒cold-proof整治regulati on 限界检查clearance examination;checking of clearance;clearanee check measurement 隧道管理系统tunnelling management system隧道环境tunnel environment隧道试验隧道实验tunnel test 试验段实验段test section 隧道监控量测隧道监控测量tunnel monitoring measureme nt 收敛con verge nee隧道安全tunnel safety隧道防火tunnel fire proofing火灾fire hazard 消防fire fighting隧道防灾设施tunnel disaster prevention equipmentsunnel anti- disaster equipment 报警装置报警器alarming device;warning device通过隧道passing tunnel避车洞refuge hole避难洞避车洞refuge recess;refuge hole 电气化铁道工程电气化铁路工程electrified railway con struction电气化铁道电气化铁路electrified railway直流电气化铁道de electrified railway交流电气化铁道交流电气化铁路a.c.electrification railway低频电气化铁道low frequency electrified railway工频电气化铁道工频电气化铁路industry frequency electrified railway电压制voltage system 电流制current system。

新奥法即新奥地利隧道施工方法的简称，原文是New Austrian Tunnelling Method 简称 NATM ，新奥法概念是奥地利学者拉布西维兹（L. V. RABCEW ICZ）教授于 50 年代提出的，它是以隧道工程经验和岩体力学的理论为基础，将锚杆和喷射混凝土组合在一起，作为主要支护手段的一种施工方法，经过一些国家的许多实践和理论研究，于60年代取得专利权并正式命名。

目录1简介 2发展历史 3支护机理 4施工原理 5主要原则 6施工特点 7施工要点 8施工顺序 9适用范围 10详细解释 11过程 12基本观点 13基本要点 14施工量测 15实际使用 16缺点 17展望未来1简介新奥法【New Austrian Tunnelling Method】新奥法是在利用围岩本身所具有的承载效能的前提下，采用毫秒爆破和光面爆破技术，进行全断面开挖施工，并以形成复合式内外两层衬砌来修建隧道的洞身，即以喷混凝土、锚杆、钢筋网、钢支撑等为外层支护形式，称为初次柔性支护，系在洞身开挖之后必须立即进行的支护工作。

因为蕴藏在山体中的地应力由于开挖成洞而产生再分配，隧道空间靠空洞效应而得以保持稳定，也就是说，承载地应力的主要是围岩体本身，而采用初次喷锚柔性支护的作用，是使围岩体自身的承载能力得到最大限度的发挥，第二次衬砌主要是起安全储备和装饰美化作用。

2发展历史1934年，新奥法主要创始人 L.V. 拉布采维茨在就试图将喷浆方法用于地下工程。

他在1942～1945年建造的洛伊布尔隧道中采用了双层薄衬砌，即先喷一层混凝土，待变形收敛后再喷一层。

1944年，他发表了有关喷混凝土的论文，并指出了围岩动态随时间变化的重要性。

1948年，又指出了量测工作的重要性。

又无公害的新喷敷方法1948～1953年喷混凝土在奥地利首次用于卡普伦水力发电站的默尔隧洞。

最早在欧洲推广使用锚杆的是1951～1953年建造的伊泽尔-阿尔克电站的有压输水隧洞。

World Tunnel Congress 2008 - Underground Facilities for Better Environment and Safety - India Construction of mined tunnel in soft ground with NATM in Pirpanjal tunnel V A(KM. 152.600 – KM. 158.730)S.D. Jeur & M. GuptaHindustan Construction Co.Ltd, Mumbai, IndiaSYNOPSIS: The case study explains the methodology and the state of art technology that was adopted in the construction of the first 650m from the South end of the Pirpanjal Tunnel Project in soft ground that consisted primarily of silty clay with boulder infested patches. The case study also reflects on the integral techniques of the NATM and how the same was utilized to suit the project requirement. It further goes on to describe the modifications to the general methodology that has to be incorporated due to the presence of fairly populated village above the alignment of the tunnel with very low overburden (20 –40m). The job required involvement of various specialized machineries. The machineries were also been detailed hereunder with their specialty.1. INTRODUCTIONThe existence of the only lifeline of transportation NH-1A connecting the planes of Jammu with the Kashmir valley has always being a point of concern. Frequent land slides and blockages in the snow bound winter times always demanded an alternative. Adding to the same,the matter that Railway network has not till date been established in this important state of ever developing India has always bothered the think tanks of Indian development. Drawing a solution, resolving the two-fold concern Northern Railways released their master plan to extend the railway service beyond Udhampur to Baramulla via Srinagar. IRCON International Limited took up the job for construction of the project from Laole to Quazigund and subletted the work of construction of the T-80 Tunnel extending from Ch. 152.600 to Ch. 163.560 to Hindustan Construction Co. Ltd. The contract work included excavation work with full support system for 10.350 km & permanent concrete lining works of 10.960 works.2. LOCATIONThe project is located in the rugged terrains of Pirpanjal Pass in the state of Jammu & Kashmir, India. The nearest towns are Banihal in the south side and Quazigund in the north side.3. PROJECT PATTERNThe total length of the T-80 tunnel is of 10.96 kms (6130m under contract Pirpanjal Tunnel V A) and is a part of the series of tunnels in the Laole Quazigund section of the Udhampur-Srinagar- Baramulla railway alignment. The construction of the tunnel was planned to be executed from three faces as under.(i) Drive from the south portal towards North(ii) Drive through Adit towards North(iii) Drive from North Portal towards SouthA diagrammatic presentation is shown in Fig.14. STRUCTURE DETAILSFigure 2 illustrates the dimension of the T-80 tunnel. The excavated profile is of a 10.077m height and 10.265m width. The tunnel structure was divided into three parts (a) Heading, (b) Benching & (c) Invert. The heading is of height 7.321m and forms the upper part of the tunnel profile. The Benching and Invert forms the balance lower part and is of 2.757m height. It’s a modified horse shoe shaped tunnel and is having an upper circumferential radius of 4.970m radius in the crown periphery. The initial supports comprised of shotcrete, lattice girder and wiremesh along with rockbolts. The final support is of 300mm RCC lining as per Rock class encountered.4. GEOLOGICAL CONDITIONFor geotechnical analysis and design the persisting rock was broadly divided into eight rock classifications. The ever-changing characteristic of the Himalayan geology was existing in this region as well. And the most difficult part for tunneling was the first 650m from the south drive towards north, which comprised predominantly of soft clay soil with patches of hard strata in between. The strata as revealed from the pre-bid soil investigation consisted mainly of soil of Rock Class VII & VIII withnil water seepage. The overburden varied between 20m to 40m. The presence of village Cheril above the alignment of the tunnel added tothe construction difficulties in tackling the ground conditions.5. TECHNOLOGY & METHODOLOGYAt the start up of the tunnelling work the false portal was developed by installing 76mm SD bolts with grouting along the profile. The 76mm mai anchors rested on the ribs erected for the portal development which was further been reinforced by subsequent shotcrete and wiremesh. Photo 1 shows the L2C during installation of the 76mm pipe roof during portal development works.In cognizance to all the geotechnical data available, New Austrian Tunnelling Method (NATM) was adopted, which was considered to be the best to suit the conditions available. The concept of distribution of the soil pressure suited the soft low overburden conditions persisting in the area. Accordingly, methodology following the concepts of NATM was decided to suit the actual conditions at site. Methodology for excavation by excavator was decided to suit the conditions and to retain the stability of the overburden soil structure. A tunnel excavator SAMBO STE 280 was deployed for the purpose. Considering the stability of the soil the tunnel top heading was excavated in sectors. Figure 3 illustrates the part excavation and the sequence that was employed.The periphery was divided into three parts leaving a face supportingbody or the core in the middle. The face supporting body is left to retain the persisting natural soil pressure.The top part is excavated first with a round length of 1.0 –1.5m, which is subsequently treated with face & wall sealing shotcrete and face wiremesh. Face bolts were installed to strengthen nthe soil further. Thereafter excavation of the left part is done. The activities of shotcrete, wiremesh and face bolts follow subsequently as before. The last periphery sector or the right part of the face is excavated hence forth. Lattice girder and wiremesh are installed as per the advancement achieved. At no point of time any part of the tunnel is left without support, any advancement that was carried out with 100% full back support. Rockbolting and further forepoling works follow the sequence. The rockbolting and forepoling work was executed with a L2C 2-Boom hydraulic drilling jumbo (Photo 2).After completion of the periphery excavation, the core or the face supporting body was been excavated in full with subsequent application of shotcrete wiremesh and face bolts. For the purpose of mucking a side tilting wheel loader is used with sufficient numbers of adequate capacity.Thereafter, the excavation cycle is rotated. A typical cycle time for1.4m advancement achieved with this methodology is shown in Table 1.A temporary shotcrete invert is constructed at the bottom of the top heading portion. The shotcrete invert consisted of shotcrete and wiremeshas well. It is constructed in order to close the circular profile arch of the top heading. It is necessarily required for the redistribution of the surrounding soil stresses to achieve the required equilibrium.This methodology was adopted till Tunnel Meter 307.80, which was thereafter modified due to the presence of a fairly populated village of Cheril above the alignment of the tunnel.6. MODIFICATION IN METHODOLOGYIn this zone, after Tunnel Metre 307.80, the ground conditions revealed a sudden characteristic change. The strata in this area comprised of silty clay infested with heavy boulder all along the tunnel section. Due to the presence of the village Cheril above drilling & blasting work was totally avoided. On the contrary the boulders in the tunnel profile were broken by the breaker of the Tunnel excavator.Considering the stability of the soil strata the face was further divided into 8 – 9 sectors. Figure 4 illustrates the sequence in which the face was excavated. The face was treated with sealing shotcrete, wiremesh and face bolts alternately after each sector excavation.In order to further reduce the working vibration developed in the tunnel, the temporary invert is being drilled with 40mm holes with a centre to centre distance of 200mm. Thereafter, breaker was used to break it. The process reduced the vibration considerably.Numbers of forepoles were increased considerably to protect thecrown. The facebolts and the rockbolts that were installed were thoroughly grouted to strengthen the strata ahead. Self Drilling type rock bolts Mai Anchor were used through out the silty clay patch of the first 650m from the South towards north. The bolts were henceforth been grouted with a Mai pump.At Tunnel Metre 521 the site observed variable shattered geology with sudden inflow of water. This yielded the works for implementation of 76mm and 114mm dia pipe roof. For the purpose of larger dia pipe roof, i.e. 114mm Casagrande forepoling rig was deployed. Accordingly tackling the differential and shearing loose soil total pipe roofing of 12m length pipes were installed round the crown.Regular drainage holes and weep holes were been drilled to drain out the seepage water. In a few places drainage holes of longer length and larger diameters were also drilled to release out the water pressure developed behind the face. The water was diverted to the drain channel maintained in the left of the tunnel from where, the water drains out through gravity flow. The problem of weakening soil condition persisted till Tunnel Metre 578. Thereafter, previous methodology of work was restored.Photos 3 & 4 shows the Casagrande forepoling rig in operation of installation of 114mm pipes.The soft soil condition persisted till Tunnel Meter 638, which caused enormous difficulties and add on precautionsdue the presence of the above village. A typical cycle time achieved with this modified methodology while tackling the variable ground conditions keeping in mind the presence of village Cheril above is slated as shown in Table 2.7. BENCH / INVERT EXCA V ATIONDuring Bench / Invert excavation the temporary shotcrete invert is first broken by the breaker. Thereafter, the left part along the profile is excavated which is followed by installation of lattice Girder sealing shotcrete and wiremesh. The right part is excavated and supported hence forth. After completion of the above two sequence the central part is excavated. After completion of the total excavation Shotcreting, wiremeshing and rockbolting were done.The activity of breaking of invert produces a lot of vibration. In order to reduce the vibration due to the presence of village Cheril above the alignment of the tunnel the temporary shotcrete invert was drilled with 41mm holes, which were thereafter broken with a breaker. This reduced the vibrations considerably.8. MACHINERIES AND MATERIALS:•Sambo STE 280: It is a 1900 RPM tunnel excavator specialized for restricted and in profile excavation. It has a rotating boom arrangement which makes it very convenient to use in restrained excavation in sectors. (Photo 5).•Cifa Shotcrete Machine with Robojet: As the primary support of excavation consisted mainly of a 350mm thick shotcrete lining, a Cifa shotcrete machine with rocket boom is very much required.•2-Boom Hydraulic Jumbo (L2C): This is a computerized version of the 2 boom hydraulic jumbo, Atlas Copco make. This is the first drill machine to be used in India with a computerized navigation system. The drill patterns were loaded in the computer of the machine, which is then aligned through 3 nos lasers. The drilling work was initiated thereafter. The position and the length of drilling is controlled by the machine computer only. The drilled hole data are automatically been stored in the computer therein, which were on a later stage retrieved for analysis. Computer generated sample shown in sample A1.1. Casagrande PG 175: This is a specialized equipment to execute the pipe roofing works and to drill longer & larger drainage holes.2. Self drilling rockbolts mai anchors: The rockbolts forms an integral part of the support measures of the tunnel in soft ground conditions. The self drilling rock bolts mai anchors are perfect to the purpose. Photos 6 & 7. It is drilled into the soil and is subsequently grouted.CONCLUSIONFor tunneling success in Himalayan geology the Casagrande forepoling rig for pipe roofing, L2C Boomer for drilling and rockbolting,Sambo STE 280 tunnel excavator, Cifa shotcrete machines or similar equivalents is a must requirement.BIOGRAPHICAL DETAILS OF THE AUTHORSS.D. Jeur diploma in Civil Engineering passed in the year 1962 from Walchand College of Engineering, Sangli. He joined Hindustan Construction Co. Ltd in the same year in the Bhira new Tunnel Project, in Maharashtra, India. Since then he is working for HCC in various underground projects such as Tunnels, Powerhouse, Desilting chambers in India & abroad under various capacities. He has vast experience in underground projects over 45 years and about 30 years in Himalayan geology. At present he is working as a Project Controller in HCC and looking after the Rail Projects in J&K and Tala hydroelectric Project, Bhutan.M. Gupta graduated in Civil Engineering from the Bengal Engineering College in 2003. From 2003 to 2004 he worked for Electrosteel Infrastructure Services as a Site Engineer, in the construction of RUIDP pipe line project for laying and commissioning of new ductile iron water supply pipe line in Bikaner, India. In 2005 he joined Hindustan Construction Company Limited, where he worked as a Contracts Engineer in the projects of Pirpanjal tunnel V A project.。