Numerical analysis on the seismic performance of subway station in ground crack area

Abstract

The site soil with ground cracks would cause strong motion and large deformation under major earthquakes, which brings a serious threat to underground structures. However, the ground crack effect on the seismic response of underground structures was unclear. This study developed a series of numerical analyses to study the seismic performance and damage mechanism of a rectangular-section subway station located in a ground crack area. After verification of the developed model, the structural responses of the subway stations in different sites subject to different earthquakes were evaluated in terms of acceleration response, inter-story drift, and damage pattern. Furthermore, a parameter analysis was performed to address the effects of structural position in the site, structural overburden depth and dynamic shear modulus of soils on the seismic performance of the subway station in the ground crack area. The results showed that the presence of ground crack exacerbated the shear deformation of the site soil and increased the internal forces of the lateral members, resulting in substantial damage to the subway station. The subway station in the ground crack area had poorer seismic performance than the station in the uncracked area, especially for station crossing the ground crack. Particularly, the ground crack effect on the seismic performance of subway stations should be carefully considered in the design of shallow-buried underground structures in soft soils.