隧道外文文献及翻译

附录二外文参考文献及翻译

NATM tunnel design principle in the construction of major and

Construction Technology

W.Broere

I.The NATM Design Principle

1.Tunnel design and construction of two major theoretical and development process

Since 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 the necessary 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. NATM

NATM 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. To

this 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 may cavern 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+Ku

Discussion :

(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, t he 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 method

NATM 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 the economy 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 and support 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 soft rock 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 technology

1. Cave construction :

（1）excavation slope around :

Lofting 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-supporting :

Yang 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 construction :

Yang 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 roof :

Sets 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 method :

Lofting 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 machinery :

N 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 catheter

A. 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 then grouting. 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 parameters :

N water slurry and water glass volume : 1:0.5;

N slurry water-cement ratio 1:1

N 35 Baume concentration of sodium silicate; The efficacy silicate modulus

N 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 construction :

Embedded 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 Construction

Installation 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 construction

Install 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 Construction

Cleared 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 control

Entrance 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 problems :

Construction 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 projects

NATM 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 of application 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.

For the "new Austrian law," the connotation of the word, people have an understanding of the development process. Just as the term itself - New Austrian Tunneling Method expressed in the , the new Austrian founder of the first as it is with a new supporting the tunnel construction method proposed. It was subsequently found that, NATM will stick to a particular method or specific technical support to implement it will be very much constrained. So, in some literature emphasized that the new Austrian law is a "concept" and "philosophy", "principle" or "channels" instead of a fixed concrete construction method or technology. Clarify this point, has important practical significance. Indeed, in some projects, As copy some of the new projects NATM method without specific attention in light of the works reflect the realities of the new Austrian law principles failure. I experienced a soft rock of

special shallow tunnel construction in the use of the new Austrian law in the process of collapse had links surface of collapse. Various reasons, which is a copy of some Heights stress formation of the tunnel, Supporting the one-sided emphasis on the soft, emphasizing the initial support facilities for the latter to release as much as possible deformation, not for the timely implementation of secondary support.

So, what is the new concept of NATM connotation? It was reduced to 22, it was reduced to seven. In fact, only one, which is to protect the rock, and giving play to rock the capacity for self. From such a principle, under specific conditions tunnel flexibility to choose the excavation, blasting, Supporting forms, and supporting facilities for the opportunity and support for France. As for the rock deformation control under different circumstances, it should be stressed that the release of a restriction should be emphasized. Its purpose is to "protect the rock, and giving play to rock the capacity for self.

新奥法设计原理在隧道施工中的应用及主要施工工艺

W.Broere

Ⅰ、新奥法的设计原理

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。

二、新奥法

新奥法即新奥地利隧道施工方法的简称，原文是New Austrian Tunnel- ling Method,简称为NATM。它与法国称收敛约束法或有些国家所称动态观测设计施工法的基本原则一致。

新奥法概念是奥地利学者拉布西维兹教授于二十世纪50年代提出的。它是以既有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，经奥地利、瑞典、意大利等国的许多实践和理论研究，于60年代取得专利权并正式命名。之后这个方法在西欧、北欧、美国和日本等许多地下工程中获得极为迅速的发展，已成为现代隧道工程新技术的标志之一。我国近40年来，铁路等部门通过科研、设计、施工三结合，在许多隧道修建中，根据自己的特点成功地应用了新奥法，取得了较多的经验，积累了大量的数据，现已进入推广应用阶段。但在公路部门新奥法的应用仅为50%左右。目前新奥法几乎成为在软弱破碎围岩地段修建隧道的一种基本方法，技术经济效益是明显的。新奥法的基本要点可归纳如下：

1．岩体是隧道结构体系中的主要承载单元，在施工中必须充分保护岩体，尽量减少对它的扰动，避免过度破坏岩体的强度。为此，施工中断面分块不宜过多，开挖应当采用光面爆破、预裂爆破或机械掘进。

2．为了充分发挥岩体的承载能力，应允许并控制岩体的变形。一方面允许变形，使围岩中能形成承载环；另一方面又必须限制它，使岩体不致过度松弛而丧失或大大降低承载能力。在施工中应采用能与围岩密贴、及时筑砌又能随时加强的柔性支护结构，例如，锚喷支护等。这样，就能通过调整支护结构的强度、刚度和它参加工作的时间（包括闭合时间）来控制岩体的变形。

3．为了改善支护结构的受力性能，施工中应尽快闭合，而成为封闭的筒形结构。另外，隧道断面形状应尽可能圆顺，以避免拐角处的应力集中。

4．通过施工中对围岩和支护的动态观察、量测，合理安排施工程序、进行设计变更及日常的施工管理。

5．为了敷设防水层，或为了承受由于锚杆锈蚀，围岩性质恶化、流变、膨胀所引起的后续荷载，可采用复合式衬砌。

6．二次衬砌原则上是在围岩与初期支护变形基本稳定的条件下修筑的，围岩和支护结构形成一个整体，因而提高了支护体系的安全度。

上述新奥法的基本要点可扼要的概括为：“少扰动、早喷锚，勤量测、紧封闭”。

三、用一个弹簧来理解新奥法原理

1．洞室边缘某一点A在开挖前具有原始应力（自重应力和构造应力）处于一个平衡状态。如同一根弹性刚度为K的弹簧，在P0作用下处于压缩平衡状态。

2．洞室开挖后，A点在临空面失去约束，原始应力状态要调整，如果围岩的强度足够大，那么经过应力调整，洞室可处于稳定状态（不需支护）。然而大多数的地质情况是较差的，即洞室经过应力调整后，如不支护，就会产生收敛变形，甚至失稳（塌方），所以必须提供支护力PE，才能防止塌方失稳。等同于弹簧产生了变形u后，在PE作用又处于平衡状态。

3．由力学平衡方程可知，弹簧在P0作用时处于平衡状态；弹簧在发生变形u后，在PE的作用下又处于平衡状态，假设弹簧的弹性系数为K，则有：

P0=PE+Ku

讨论：

（1）当u=0时，P0=PE 即不允许围岩变形，采用刚性支护，不经济；

（2）当u↑时，PE↓；当u↓时，PE↑。即围岩发生变形，可释放一定的荷载（卸荷作用），所以要允许围岩产生一定的变形，以充分发挥围岩的自承能力。是一种经济的支护措施，围岩的自稳能力P=P0-PE=Ku；

（3）当u=umax时，发生塌方，产生松驰荷载，不安全。

四、要点

1．围岩是受洞室开挖影响的那一部分岩（土）体，围岩是三位一体的即：产生荷载、承载结构、建筑材料。

2．隧道是修筑在应力岩体中的，具有特殊的建筑环境，不能等同于地面建筑。

3．隧道结构体系=围岩+支护体系。

Ⅱ、新奥法在公路施工中的基本方法

新奥法的特征之一是采用现场监控，量测信息指导施工，即通过对隧道施工中量测收据和对开挖面的地质观察等进行预测、预报和反馈。并根据已建立的量测为基准，对隧道施工方法、断面开挖步骤及顺序、初期支护的参数等进行合理调整，以保证施工安全，坑道围岩稳定、工程质量和支护结构的经济性等。笔者对承（承德）赤（赤峰）东线茅荆坝隧道采用新奥法基本施工方法作了调查总结，

综合出公路隧道采用新奥法施工的种类及选用不同基本施工方法的特点及注意事项。

一、隧道施工方法选择隧道施工方法的选择，主要根据工程地质及水文地质条件、施工条件、围岩类别、隧道埋置深度、隧道断面尺寸大小和长度衬砌类型，应以施工安全为前提及以工程质量为核心，并结合隧道的使用功能，施工技术水平、施工机械装备、工期要求和经济可行性等因素综合考虑研究选用。

当选择施工方法因隧道施工对周围环境产生不利影响时，也应把隧道工程的环境条件作为选择施工方法的因素之一，同时应考虑围岩变化时施工方法的适用性及其变更的可能性，以免造成隧道工程失误和增加不必要的工程投资。采用新奥法施工时，还应考虑施工全过程中的辅助作业方式和对围岩变化的量测监控方法，以及隧道穿越特殊地质地段时的施工手段等进行合理的选择。

二、新奥法隧道施工方法方案隧道新奥法施工常用方法大致分为全断面法、台阶法和分部开挖法三大类及若干变化方案。

（一）全断面法。即全断面开挖法，是指按设计开挖面一次开挖成型。其开挖顺序是全断面开挖，锚喷支护，灌筑砼衬砌。常选用于Ⅳ－Ⅵ类硬岩的石质隧道，该法可以采用深孔爆破。

全断面开挖法有较大的作业空间，有利于采用大型配套机械化作业，提高施工速度，且工序少、干扰少，便于施工组织和管理。缺点是由于开挖面积较大，围岩相对稳定性降低，且每循环工作量相对较大，因此就要求施工单位应具有较强的开挖、出渣与运输及支护能力，茅荆坝Ⅵ：V类围岩中采用了全断面开挖，达到了预期效果。

全断面施工开挖工作面大，钻爆施工效率较高，采用深眼爆破可加快掘进速度，且爆破对围岩的振动次数较少，有利于转帐岩稳定。缺点是每次深孔爆破震动较大。因此要求进行精心的钻爆设计和严格控制爆破作业。

全断面开挖法的主要工序是：使用移动式台车（或者台架），首先全断面一次钻孔，并进行装荷连线，然后将钻孔台车后退到50m以外的安全地点，再起爆，使一次爆破成型，出渣后钻孔台车再推移至开挖面就位，开始下一个钻爆作业循环，同时进行锚喷支护或先墙拱后衬砌。

（二）台阶法。台阶法一般是将设计断面分成上半断面和下半断面两次开挖成型。其开挖顺序是上半部开挖拱部锚杆喷射砼支护，拱部衬砌，下半部中央部分开挖，边墙部分开挖，边墙锚杆喷射砼支护及衬砌。该方法多适用于Ⅱ、Ⅲ类

较软而节理发育的围岩中，可分别采用添中变化方案。

长台阶法：上下台阶距离较远，一般上台阶超前50m以上，施工中上下部可配属同较大型机械进行平行作业，当机械不足时可以交替使用，当遇短隧道时，可将上部断面全部挖通后，再挖下断面，该法施工时干扰较少，可进行单工序作业。

短台阶法：上台阶长度5－50m，适用于Ⅱ、Ⅲ类围岩，可缩短仰拱封闭时间，改善初期支护受力条件，但施工干扰较大，当遇到软弱围岩时需慎重考虑，必要时应采用辅助开挖措施稳定开挖面，以保证施工安全。

超短台阶法：上台阶仅超前3－5m，断面闭合较快。此法多用于机械化程度不高的各类围岩地段，当遇到软弱围攻岩时需慎重考虑，必要时应采用辅助施工措施稳定开挖工作面，以确保施工安全。

台阶开挖的特点在于，一是台阶开挖宜采用轻型凿岩机打眼，而不宜采用大型凿岩台车。二是台阶法开挖具有足够的作业空间和较快的施工速度。台阶有利于开挖面的稳定性。尤其是上部开挖支护后，下部作业较为安全。三是台阶法开挖的缺点是上下部作业互相干扰。应注意下部作业时对上部稳定性的影响，台阶开挖会增加对围岩的扰动次数。

（三）分部开挖法。分部开挖法可分为五种变化方案：台阶分部开挖法、上下导坑法、上导坑超前开挖法、单（双）侧壁导坑法。是将开挖断面进行分部开挖逐部成型，并且将某部分超前开挖，故此可称为导坑超前开挖法。

台阶分部法：适用于一般土质或易坍塌的软弱围岩地段，其优点与超台阶法相比，台阶可以加长，一般双车道隧道为1倍洞跨，单车道隧道为2倍洞跨；而较单（双）侧臂导坑法机械化程度高，可加快工程进度。

上下导坑超前开挖法（即上下导坑先拱后墙法）：此法适用于Ⅱ、Ⅲ类围岩，在松软地层开挖隧道，一般宜采用上下导坑超前开挖先拱后墙法。其优点是：导坑超前开挖，利用提前探明地质情况，便于改变施工方法。工作面多，便于拉开工序，适用于安排劳动力与使用小型机械施工。该方法缺点：上下导坑断面小，则施工速度慢，施工工序较多，使施工组织和管理难度大。

单侧臂导坑法：围岩稳定性较差，隧道跨度较大，地面沉陷难以控制时采用此方法。其特点是：有正台阶法和双臂导坑法的优点。

双侧臂导坑法：适用于浅埋大跨度隧道，地表下沉量要求严格，围岩特别差时采用。此法优点是：施工安全可靠，但施工速度较慢，造价高。

Ⅲ、隧道主要施工工艺

一、洞口段施工：

1、边仰坡开挖：

全站仪测量放样，利用挖掘机自上而下逐段开挖，不得掏底开挖或上下重叠开挖，清除洞口与上方有可能滑塌的表土，灌木及山坡危石等，石质地层仰坡开挖需要爆破时，应以浅眼松动爆破为主。局部也可人工配合修整，开挖时应随时检查边坡和仰坡，如有滑动、开裂等现象，应适当放缓坡度。

2、成洞面支护：

仰坡刷坡完成后，及时用坡度板检查坡度，待坡度检查合格后，及时打设系统锚杆，并将锚杆头外露，挂设金属扩张网与锚杆头焊接成整体。挂网完成后立即喷射混凝土，并反复喷射，直到达到设计厚度为止。

3、截水沟施工：

在距仰坡坡口5米处开挖截水沟，截水沟开挖以机械为主，人工配合修整，修整完后，立即砌筑7.5#浆砌片石，并用砂浆抹面。

二、辅助施工：

1、长管棚：

套拱施工：施工放样，模板安装、钢筋绑扎、导向管放样，127导向管安装，砼浇注。

钢管规格：热扎无缝钢管￠108㎜，壁厚6㎜，节长3米，6米；

n 管距：环向间距50㎝；

n 倾角：仰角1°（实际施工按2°施工），方向与线路中线平行；

n 钢管施工误差：径向不大于20㎝；

n 隧道纵向同一截面内接头数不大于50%，相邻钢管的接头至少错开1米。

A 管棚施工方法：

测量人员准确放样，标出洞中心线及拱顶标高，开挖预留核心土作为管棚施工的工作平台，开挖进尺为2.5米，开挖结束后，人工两边对称开挖（品字型）工作平台，台阶宽度1.5米，高度2.0米，作为施工套拱和管棚施钻的平台。管棚应按设计位置施工，应先打有孔钢花管，注浆后在打无孔钢花管，无孔管可作为检查管，检查注浆质量，钻机立轴方向必须准确控制，以保证孔口的孔向正确，每钻完一孔便顶进一根钢管，钻进中应经常采用测斜仪量测钢管钻进的偏斜度，