楼板开孔时地铁车站端头井结构抗震分析

Seismic Analysis on End Well for Metro Station with Floor Opening

结合上海软土地区某叠合墙地铁车站,利用Midas Gen数值软件,对端头井楼板按照实际开孔布置和超大开孔布置分别建立三维数值模型并采用反应位移法计算分析。结果表明,随着楼板开孔宽度占比增加,楼板结构、端头井结构在水平面内抗侧刚度仅小幅减小,影响有限,但会直接削弱楼板对侧墙的约束作用致侧墙跨中弯矩显著增加。楼板开孔宽度超限并不会直接导致设防、罕遇地震作用下端头井结构层间位移角超限,其抗震变形仍满足规范限值要求,而设防地震作用下结构截面、配筋设计等仍由静力工况控制,抗震工况非控制工况,但必要时应采用土层-结构时程分析法并计入竖向地震作用,确保地铁端头井结构抗震承载力和变形满足要求。

Based on a metro station of superimposed wall in Shanghai,two three-dimensional models of actual floor opening and large floor opening are established to conduct calculation and analysis using the Midas Gen finite element numerical software by response displacement method.The results demonstrate that:when the proportion of floor opening width in end well increased greatly,the lateral stiffness of the floor structure and the end well structure in horizontal plane decreased slightly with limited influence,large floor opening directly weakens the restraint of floor on side wall,leading to a significant increase in the mid-span bending moment of side wall;the over-limit of floor opening width does not directly lead to the over-limit of the calculated displacement angle between layers under E2、E3 earthquake,its seismic deformation still meets the standard limit,and the structure section size and reinforcement are still controlled by static condition not earthquake condition,however,it is necessary to conduct calculation and analysis to ensure the seismic bearing capacity and deformation of metro end well structure meet the requirements by soil-structure time history analysis method when vertical earthquake considered.