Seismic performance of underground subway station structure considering connection modes and diaphragm wall

Abstract

In the seismic design of underground subway station structures, the influence of side diaphragm walls as safety factor is not considered. In general, the role of the diaphragm wall has not been adequately investigated. In this study, an advanced finite element analysis model was developed to simulate the dynamic interactions among the soil, underground diaphragm walls, and subway station by considering different connection modes for the diaphragm wall and sidewall and the effect of the initial static stress. The influences of the diaphragm wall and its connection to the sidewall of the underground subway station were analyzed and compared. The results show that the existence of diaphragm wall will strengthen the lateral stiffness and reduce the lateral deformation of underground subway station, however, in some cases, it is not entirely for preventing a seismic damage in the underground subway station; Rather, a slipping connection between the diaphragm wall and side wall exacerbates the earthquake damage in the middle column of the underground structure under a strong ground motion input. However, a tied connection between the diaphragm wall and sidewall improves the seismic responses of the underground subway station.