基于IDA方法的两层三跨地铁地下结构地震易损性分析

Seismic fragility analysis of two-story and three-span metro station structures based on IDA method

以两层三跨地铁车站为研究对象,建立典型工程场地下的土–结构非线性相互作用分析模型,将基于IDA方法的结构地震易损性分析方法引入到地铁车站结构中,初步探讨适用于浅埋地下结构的地震动强度指标IM及地下结构地震响应随地震动幅值增大的变化规律,并建立浅埋地铁车站结构抗震易损性曲线,得到结构在不同地震烈度水平下的失效概率。分析结果表明:非自由场下地表处的PGA为合适的IM指标;与已有经验易损性曲线的对比结果表明易损性分析方法是可行的,可以定量的给出结构在不同性能水准下的失效概率,为地下结构的抗震设计提供参考。

Based on the non-linear soil-structure interaction model for a two-storey and three-span metro station in a typical underground engineering site,an IDA(incremental dynamic analysis)-based structural seismic fragility analysis method is introduced for underground metro station structures.The earthquake intensity measure IM suitable for the underground structures is proposed,and the change of their seismic response with the increase of earthquake amplitude is preliminarily discussed.The seismic fragility curves of shallow-buried metro station structures are established,and the failure probability of structures under different seismic intensity levels is obtained.The results show that PGA is an appropriate IM under non-free field,and comparison of the numerical results with the fragility curve of other scholars shows that the proposed fragility analysis method is feasible,and can quantitatively give the failure probability of structures at different performance levels,and provide reference for seismic design of underground structures.