Study on safety control for Wuhan metro construction in complex environments

Open cut method is adopted in the foundation pit construction of Wuhan Metro Line 2 (WML2) XunLiMen Station which is under the bridge of the (existent) operating light rail. The foundation pit is only 1.25 m away from the nearest pier of Wuhan Light Rail Line 1 (WLRL1).Safety control of this project focuses on how foundation pit construction affects the safety of light rail bridge and its operation. In this paper, finite difference software FLAC3D for geotechnical engineering is applied to simulating the process of the foundation pit excavation and to analyze the impact of the isolation pile construction, the underground diaphragm wall construction and the foundation pit dewatering and excavation on the bridge piers of WLRL1, while the finite element software ANSYS is used to simulate the numerical model of WLRL1. Moreover, the study of the impact of the construction scheme of WML 2 on the operation of WLRL1 is also presented in the paper. Finally, on the basis of the simulation results, (the) control standards for the operation safety of WLRL1 and (the) advices for the safety control of the foundation pit construction, which proved to be successful, are proposed.