由于近年来城市地下空间的开发,修建了一大批地铁车站,这些大尺度地下结构的出现,为工程抗震提出了新的课题.首先详细阐述了基于设计反应谱合成空间相关多点地震波的方法,合成的地震波不仅具有地震动的空间相关性,同时还具有强度和频率含量的双重非平稳性;再分别建立了位于三种场地中的地铁车站三维有限元模型,用无限单元来模拟无限域的影响,在此基础上分析了一致与非一致地震动输入情况下该地铁车站的地震响应特征.结果表明:在软土场地中,地震动的非一致性使车站轴向各中柱位移产生了较大的相位差,同时对侧墙的动应力影响较大;在中等和硬土场地中,地震动的非一致性对结构的动力响应影响较小,一般可以忽略.建议在对软土场地中的大尺度车站结构进行地震反应分析时,应考虑地震动的非一致性影响.%Because of exploitation of urban underground space recently, a lot of large-scale subway stations were built. So, a new issue appeared for engineering design. The procedures for artificial simulation of multi-point seismic waves based on the code response spectrum were presented here. The generated seismic waves were spatially correlated to the ground motion, and had the double non-stationary properties of strength and frequency. The three-dimensional numerical models of a subway station were established under three different site conditions, and the infinite domain of soil was simulated with an infinite element. On this basis, the seismic responses of the subway station under non-uniform ground motion were analyzed compared with those under uniform seismic excitation. The results showed that horizontally relative displacements between top and bottom at different axial sections of the subway station have a great phase difference in soft sites because of non-uniform seismic action, and the effect on the dynamic stress of the side wall is great; the influence of the non-uniform feature on the dynamic response of the station is insignificant in medium hard sites and hard sites; a suggestion is given that the spatially multi-support earthquake excitations must be considered in the seismic analysis of a large-scale subway station in soft sites.
展开▼
