考虑非一致地震输入的地铁车站动力时程分析

Dynamic time-history analysis of subway station considering non-uniform seismic input

为了研究非一致地震输入以及考虑土体介质阻尼的自由波场对大型地铁车站动力响应的影响,发展了一种可考虑土体介质阻尼影响的自由波场一维化时域有限元算法,并编制了相应的非一致地震波动等效荷载的Matlab计算程序;以一典型两层双柱岛式地铁车站为工程背景,建立三维地铁车站结构-土相互作用系统的整体有限元数值模型,开展动力时程实例分析。计算结果表明:与地震波一致输入情形相比,地震波非一致输入将引起地铁车站结构的控制内力和层间位移分布及其幅值发生明显变化;与不考虑土体介质阻尼的地震波动输入相比,在考虑土体介质阻尼的地震波动输入下,地铁车站结构的控制内力和最大层间位移均有一定幅度的减小,且减小幅度随波动入射角的增大而增大。本文分析表明,非一致地震波动输入及土体介质阻尼对大型地铁车站结构的动力时程响应均有一定影响。

In order to study the influence of non-synchronous excitation and the free field that considering soil media damping on dynamic response of large subway station, a 1 D time-domain finite element method for seismic wave motion of free field in layered media was developed, which considers the effect of soil media damping. A pro- gram for equivalent load of non-synchronous excitation has been developed with Matlab programming language on the basis of the method. Based on a typical two-layer double-column subway station, a 3D finite element model of the whole subway station structure-soil interaction system was built, and dynamic time-history analysis for the whole system under Dirac pulse excitation was carried out. The results show that, compared with synchronous input, the distributions and amplitudes of the control internal forces and story drifts of the subway station structure change sig- nificantly under non-synchronous input; compared with the wave input without considering soil medium damping, both the control internal forces and the maximum story drifts decrease in a certain extent under the wave input con- sidering soil medium damping, and the decrease amplitude increases with increasing angle of incidence wave. It can be drawn from this paper that, both the non-uniform seismic wave input and the soil media damping have sig- nificant influence on dynamic time-history response of large subway station structures.