Research Progress of Subway Tunnel Passing Through Xi′an Ground Fracture and Application Prospect of "Shield Tunnelling before Expansion" Method
(1. School of Highway, Chang′an University, Xi′an 710064; 2. Guangzhou Metro Design Institute Co., Ltd., Guangzhou 510010;3. Xi′an Rail Transit Group Co., Ltd., Xi′an 710018)
Abstract：
Xi′an ground fracture is a typical geological disaster in the loess area, which covers almost the whole ur? ban area. Its creep activity seriously endangers the safety of subway tunnels, which is a major technical problem in subway construction. Based on the ground fracture prevention and control experience of Xi′ an Metro for more than ten years, this paper systematically sorts out the distribution and activity characteristics of ground fractures, the hazards faced by the metro, the concept and measures of fortification, the fortification parameters, the operation of fortification structures, etc. It focuses on the analysis of the problems existing in the conventional construction method of "mined excavation + shield stepping", and puts forward a new construction technology of "shield tunnelling before expansion". The main conclusions are as follows: (1) The conventional construction method of metro passing through a ground fracture section involves a series of complex processes such as shaft and cross passage excavation, manual operation with CRD method, shield stepping, etc. The contradiction between the necessity of fortification and the complexity of existing construction technology seriously restricts the construction process of the Xi ′ an metro. (2) The construction process, problems to be solved and engineering application prospects of the new construction method of "shield tunnelling before expansion" are given. (3) The "shield tunnelling before expansion" method ensures the continuity of shield operation, avoids the launching and receiving in the shield tunnel, and then reduces the fortification section under the same fortification parameters through the optimization of structure and construction method,which is an important exploration and attempt to realize the convenient and low-cost ground fracture section of the subway tunnel.
LAI Hongpeng1 YAO Yi1 GAO Qiang2 KANG Zuo3
.Research Progress of Subway Tunnel Passing Through Xi′an Ground Fracture and Application Prospect of "Shield Tunnelling before Expansion" Method[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(1): 23-33
2023, Vol. 60 
