软弱围岩初始地应力下的衬砌受力分析

Stress Analysis of Tunnel Lining Under Soft Rock Initial Stress

结合某隧道工程实例,利用有限元分析方法和工程类比法。分析隧道衬砌在软弱岩层不同初始地应力作用下的受力和围岩的变形情况。得出随着围岩初始地应力的增加,围岩的最大水平和竖直位移、锚杆和初支最大轴向应力接近线性增加趋势,且随初始地应力的改变,最大值节点的值仍为最大。与初支相比二次衬砌受力极小,证明其具有安全储备的作用。这一结果与施工现场观察的现象基本吻合,为今后软弱围岩条件下隧道衬砌支护设计起到参考性价值。

Based on a given tunnel project,FEM and engineering analogy methods are used to analyze deformation of surrounding rock and stress of tunnel lining under different soft rock initial stress.The results show that with the initial stress increasing of the surrounding rock,rock maximum horizontal and vertical displacement,the bolt maximum axial stress and the early support maximum axial stress increase approximately linearly,and with the change of initial stress,the maximum value at node is still the largest.Compared with the first support,the second lining stress is very small,which proves that second lining can realize security reserve.This result is basically consistent with the observed phenomenon in construction site,which can provide referential value for support design under conditions of soft surrounding rock.