基于修正惯用法的埋深对圆形隧道地震反应影响

Seismic Performance of Circle Tunnels Affected by Buried Depth Based on Modified Routine Method

采用修正惯用法,在考虑土拱效应对圆形隧道结构受力状态影响的基础上,研究了埋深对地下结构地震反应的影响规律。首先,对比分析了不考虑和考虑土拱效应时、地震荷载作用前,隧道结构内力分布及随埋深的变化规律;将作用于隧道结构上的水平地震荷载等效为围岩土体变形导致的土压力的改变值;继而探讨了考虑土拱效应后,地震荷载引起的隧道结构内力的改变,研究了不同地震动强度下,埋深对圆形隧道结构地震反应的影响规律。研究结果显示,地震作用下,圆形隧道结构的内力随着埋置深度的增加呈现出先增大后减小或趋于稳定的趋势,即圆形隧道结构地震反应存在一个抗震关键埋深。

By taking into account the arch effect influencing the internal forces within circular tunnels,the seismic performance of tunnels affected by the buried depth was discussed based on the modified routine method.The internal force distributions of tunnel structure and their variations with buried depth before the earthquake considering and without considering soil arching effect are compared and analyzed.The seismic loads imposed on the tunnel are equivalent to the change in soil pressure caused by the deformation of surrounding soils.Then the internal forces within the tunnels caused by the seismic loads with different earthquake intensities are illustrated by considering the arch effect,and the buried depth influencing the seismic performance of tunnels is analyzed.It presents that,the internal forces within the tunnel get larger with the increase in buried depth and then decrease or became stable.There is a critical buried depth for the seismic performance of the circular tunnel.