饱和砂土场地中地铁车站结构地震易损性分析

SEISMIC VULNERABILITY ANALYSIS OF SUBWAY STATION EMBEDDED IN SATURATED SAND LAYERS

  • 摘要: 为进一步研究饱和砂土场地中地铁车站结构地震易损性问题,以某单层双跨地铁车站为研究对象,综合考虑场地类别、地震动不确定性的影响,采用u-p格式饱和两相介质有效应力动力求解方法,建立饱和砂土场地-地铁车站结构体系耦合动力非线性分析数值模型,选取最大层间位移角为结构损伤指标,基于增量动力分析IDA法获得结构在地震作用下动力响应数据,进而构建地铁车站结构的地震易损性曲线,并求得结构在各级地震动作用下的不同破坏状态超越概率。分析结果表明:当PGA<0.7 g时,饱和砂土场地中地铁车站结构以发生中等损伤和轻微损伤为主;当PGA≥0.7 g时,结构以严重损伤为主,并且向坍塌发展。此饱和砂土场地中地铁车站结构地震易损性分析流程方法,可为地铁车站抗震设计和减灾预测评估提供参考。

     

    Abstract: 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.

     

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