【正文】 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 河南理工大學(xué)本科設(shè)計畢業(yè)論文 17 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) Fullface 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 IVVI 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 anization and management. Excavation is due to shortings 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 fullface excavation to achieve the desired results. Fullface 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 河南理工大學(xué)本科設(shè)計畢業(yè)論文 18 deep hole blasting vibration larger. Therefore require careful drilling and blasting design and strict control of blasting operations. Fullface excavation method is the main process : the use of mobile carts (or platforms), the first fullface 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 halfsection 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. Longstep 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 550m apply to Ⅱ , Ⅲ rock 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 35m, 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 河南理工大學(xué)本科設(shè)計畢業(yè)論文 19 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 shortings 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 twolane tunnel for a holefold, cycling Road Tunnel hole 2 times。 N pipe from : Central to the distance 50 cm。 (the actual construction works by 2 176。 N pipe construction error : Radial not more than 20