浅埋大跨隧道地震响应特性静-动力分析

以一个浅埋暗挖地铁车站为背景,应用地下结构静-动力分析方法,首先采用有限元荷载释放法模拟该地铁车站施工过程,然后采用动力有限元分析了该地下结构在地震荷载作用下的动力响应。分析结果表明,浅埋地铁车站采用先拱后墙法施工时,上台阶左侧(即先开挖一侧)大拱脚处的初衬区域应力较大;在地震荷载作用下,浅埋地铁车站结构内轮廓位移、速度和加速度动力响应峰值最大值出现在直墙顶端或附近区域,第一主应力峰值最大值与第三主应力峰值最小值分别出现在拱腰区域与右直墙底部。地铁车站结构静力和动力分析中高应力区出现在不同部位,其抗震设计中应分别对这些部位进行加强。

Analysis of Seismic Response for Shallow Embedded Tunnel with Large Cross- section by Static-Dynamic Analysis Method

Based on a shallow embedded metro station structure excavated with undermining method, its construction process was firstly simulated with load releasing method of finite element, then its dynamic response under seismic load was calculated with dynamic finite element method, to which the static-dynamic analysis method of underground structure was applied. The results indicated that while the metro station was constructed with the first-arch-then-sidewall construction method, its biggest stress was in the first lining area of the arch feet on the left side of the upper step, namely the firstly excavated side. Its biggest value of dynamic response peaks in the displacement, velocity and acceleration curves was at the top of the sidewall or in the nearby area. The maximum of the first principal stress peaks and the minimum of the third principal stress peaks were in the arch side area and the bottom area of the sidewall, separately. The high stress areas appeared in different parts of the metro station structure in the static analysis and the dynamic analysis. Therefore, these parts of the structure should be reinforced separately in the anti-seismic design.