Statistical numerical method for determining seismic performance and fragility of shallow-buried underground structure

Abstract

Currently, research on the underground structures seismic fragility is still in its infancy state. In this study, we carried out numerical simulation on soil-underground structure system (SUSI) by taking the Daikai metro station damaged in the Kobe earthquake as analysis object. Considering input ground motion characteristics, based on incremental dynamic analysis (IDA method), a statistical numerical modeling method was established to classify underground structure seismic damage status and its seismic performance level. The analysis results showed that the input ground motions had a significant effect on the IDA curves. The rationality and randomness of the selected ground motions were important influencing factors to ensure the underground structures seismic fragility curves. In relation to the damage that occurred to the Daikai station in 1995, the peak ground acceleration (PGA) and peak relative lateral displacement (PRLD) of the site were suitable for estimating the seismic performance of the shallow buried structure constructed. Finally, the seismic fragility curves were compared with the existing research results, and a seismic damage assessment was carried out, which verified the effectiveness of the statistical numerical modeling method developed in this study.