地震作用下地铁车站横截面变形的影响因素研究

A study on affecting factors of seismically induced drift of subway station

基于地下结构在地震作用下的反应特征,通过建立合理的计算模型,计算不同结构刚度、接触面摩擦系数以及地震波等条件下地铁车站的最大层间位移变形。构建不同周期的正弦简谐波,分析荷载的周期对车站横截面最大层间位移的影响。研究结果表明:结构相对刚度越小,其层间位移变形越大;对于刚度大的地铁车站,周围土体对结构的约束作用越弱,其最大层间位移变形越小;对于柔度较大的车站结构则出现相反的变化;正弦简谐加速度波作用时,简谐波周期超过2s后,最大层间位移变形与简谐波周期呈指数增长趋势;在低频段,简谐波的最大位移值控制地铁车站的最大层间位移变形。

Based on the characteristics of seismic response of underground structures, proper calculation model and parameters were developed to calculate seismically induced lateral drift and damage distribution of subway station using FEM simulation. First, the maximum lateral drift deformation of subway station was analyzed in terms of different flexibility ratios, frictional coefficients and different earthquake waveforms. Then harmonic acceleration histories with same maximum amplitude but different periods were constructed to analysis its effect on lateral drift deformation of subway station. Moreover, we constructed harmonic displacement histories with different periods to analysis its effect on lateral drift deformation. The results in this study shows that: the maximum lateral drift deformation increases with flexibility ratio; for subway stations with large lateral stiffness, stronger constrain effects between station and its surrounding soil would induce larger lateral drift deformation and vice versa; when the periods of applied sinusoidal harmonic acceleration histories exceed 2s, the maximum lateral drift would exponentially increase with the periods; in low-frequency, the maximum lateral drift deformation would depend on the maximum amplitude of input displacement histories.