Study On Adaptability For NATM And Shield Driven Method In Metro Construction

Since 1860, the metro has already developed fleetly by engineering practice more than 140 years. The construction methods being seasoned with different arounding rock condition and environment request are created, based on advanced science and technology in tunnel.NATM and shield driven method are two main kinds of underground excavation construction methods in urban metro works. The concept, principle, characteristic, adaptability condition, construction flow, application and development of the NATM and shield driven method are discussed respectively. The two construction methods in stratum, adaptability of structural transect, security, construction quality, construction schedule, cost, construction arts and crafts etc are analyzed and compared synthetically. The results show that the NATM and shield driven method have respective excellence and appearance in metro line at one time. NATM has relatively matured at home at present, and is the same with different stratum condition and groundwater condition under using corresponding assistant construction method. NATM is appled widely, and is an indispensable dark excavation in metro building. The metro is constructed by shield driven method, it's excellence is safety, fleetness and ensuring engineering quality. Shield driven method is the same with all of stratum under using Mud Press Balance shield, Earth Press Balance shield and complex shield, and have obviouse advantages in relatively weak statum, high underwater table and traversing under river etc. in particular.In metro building at home for the future, the sectional tunnel will be constructed by shield driven method, and metro station will be constructed by NATM or open excavation method, and the other tunnel of variational transection such as parking line tunnel etc will be built by using NATM based on the sectional tunnel constructed by shield driven method.