基于FLAC^(3D)模拟不同落差断层下隧道围岩稳定性分析

Stability Analysis of Tunnel Surrounding Rock Under Different Drop Faults Based on FLAC 3D Simulation

以狮子洋隧道工程为分析原型,利用FLAC^(3D)数值分析软件模拟4个不同落差的断层,旨在研究不同落差断层下隧道开挖前中后围岩应力和应变的变化特征.研究结果表明:断层破碎带处的初始地应力分布不均匀,在断层破碎带处会有一定的波动;在开挖至断层破碎带时,围岩应力会急剧下降,隧道变形也会激增;随着断层落差的增大,隧道开挖所产生的影响范围也随之增大,断层破碎带处的隧道位移更大更集中,隧道围岩应力的分布也更加不均匀,主要表现为断层处围岩应力下降幅度更大,隧道应力集中处的应力也更大更集中.

Taking Shiziyang Tunnel project as the analysis prototype,this paper simulates four faults with different drop by using FLAC^(3D) numerical analysis software,in order to study the variation characteristics of stress and strain of surrounding rock before,during and after tunnel excavation under faults with different drop.The results show that the initial in-situ stress distribution in the fault fracture zone is not uniform,especially in the fault fracture zone.When excavating to the fault fracture zone,the surrounding rock stress will drop sharply and the tunnel deformation will surge.With the increase of fault drop,the influence range caused by tunnel excavation also increases,the tunnel displacement at the fault fracture zone is larger and more concentrated,and the stress distribution of tunnel surrounding rock is more uneven,which is mainly reflected in the greater decline of surrounding rock stress at the fault,and the stress at the stress concentration of tunnel is also larger and more concentrated.