根据大量震害资料的调查分析发现,地下结构埋置深度对其地震破坏程度影响很大。通过有限元方法计算8种不同埋置深度条件下的山岭隧道地震响应,并对计算模型的地震输入方法进行了验证,证明地震波输入处理方式的合理性。讨论埋深对结构动力响应的影响,提取衬砌关键节点的竖直向和水平向加速度、位移峰值,分析随着埋深的增大,加速度和位移峰值的变化情况,并以拱顶为例,计算每个埋深变化段的加速度和位移峰值变化率,得到了一定的规律性,如埋置深度从5 m增大到50 m,衬砌结构动力响应峰值大小下降较快。此外,还分析了埋深增大对衬砌结构内力峰值的影响。最后,提出在高烈度地震区修建隧道时其埋置深度尽可能不小于50 m,这为相关工程的修建提供了参考依据。
According to a large number of findings on seismic hazards, the damages of tunnels during earthquakes depend on tunnel depth to a great extent. In order to study the effect of tunnel depth on lining, the earthquake responses of mountain tunnel in eight different depths are calculated by using the finite element method; and the seismic force loading method is verified, which confirms the rationality of the seismic load input method. In order to analyze the change of peak acceleration/displacement with increasing tunnel depth, the results of peak acceleration/displacement in both horizontal and vertical directions on key nodes of lining are extracted; and the influence of different tunnel depths on structural dynamic response is discussed. Some rules that the dynamic parameter peaks of lining decreased rapidly when the tunnel depth increases from 5 m to 50 m are found when calculating the ratio of peak acceleration/displacement on the section of different tunnel depths at vault. In addition, the influence of tunnel depth on peak internal force at tunnel vault is analyzed. And the comparative analysis between the results of the finite element calculation and the model test is made. Finally, the conclusion can be obtained that tunnel depth could not be less than 50 m when constructed in high-intensity earthquake zone, so as to provide reference for related projects.