走滑断层位移作用下山岭隧道非线性反应分析

Nonlinear analysis of mountain tunnels under strike-slip fault movement

为了研究穿越断层的山岭隧道结构在走滑断层位错作用下的反应,基于有限元和拟静力的基本原理,建立了隧道围岩的相互作用模型,提出了一种以围岩沿断层位错为输入荷载的跨断层隧道衬砌的反应分析方法。利用有限元分析软件ANSYS的位移荷载功能,使该反应分析方法得以实现。分析过程中以上盘为主动盘,通过给上盘施加强制位移来描述围岩的错动,采用荷载步为100步的逐步加载的方式来描述围岩错动的过程。对比研究了走滑断层工况下,加载断层位错由小到大的过程中,隧道衬砌各部分的应力反应状态。结果表明:当断层位错在20cm以下时,隧道衬砌各部分均处于安全状态;随着错动量的增大,衬砌不同部分的破坏顺序为:边墙先产生破坏,然后顶板产生破坏,最后破坏延伸至底板。

In order to study the character of cross-fault mountain tunnel under strike-slip fault dislocation,the interaction model between the rock and the tunnel is made on the basis of the principle of the finite element and the pseudo-static method.The method for analyzing the nonlinear responses of the cross-fault tunnel under load of fault dislocation is also developed.The analysis is performed by using the displacement function of finite element soft-ware ANSYS.The effect of fault dislocation is simulated by imposing displacement load on the hanging wall rock. The values of displacement load are imposed by 100 steps to describe the loading process.With the increase of fault dislocation,the stress states of the tunnel under the condition of strike-slip fault are analyzed.By the computation, some meaningful results have been obtained：（1）The tunnel is under safe state,when the fault dislocation is smaller than 20 cm.（2）The wall of tunnel is the easiest to be damaged,then the roof,and the damage to the bottom is at the last.