SEISMIC VULNERABILITY ANALYSIS OF SUBWAY STATION EMBEDDED IN SATURATED SAND LAYERS

In order to further investigate the seismic vulnerability of a subway station structure embedded in saturated sand layers, a numerical model of one-story subway station with double spans in saturated sand layers is established based on the u-p effective stress formulations of two-phase media, considering the influence of both site type and ground motion uncertainty. On this basis, the corresponding exceedance probability and vulnerability curves are obtained by using incremental dynamic analysis method, with respect to the damage index of the maximum drift angle for inter-story displacement. The results show that: when PGA<0.7 g, the seismic loads will result in slight or moderate damage in subway station structure; when PGA≥0.7 g, severe damage will occur with the tendency to collapse. This proposed approach of seismic vulnerability for subway station structure in saturated sand layers can provide guide for seismic design of subway station structure as well as prediction for disaster prevention.