摘要
姜源岭隧道进口段埋深较浅,围岩主要为全～强风化花岗岩,裂隙发育。在建设过程中,降雨导致右洞Yk32+366断面发生塌方。在分析塌方事故原因的基础上,借助数值模拟软件FLAC3D,对塌方过程中围岩的渗流场、位移场及作用于支护结构上的作用力进行了分析,研究了塌方的机理。研究表明:降雨条件下,围岩孔隙水压力增加,水致弱化效应增强,岩土体的粘聚力及内摩擦角变小,围岩整体稳定性降低。随着隧道开挖,孔隙水从开挖面渗流,围岩孔隙水压力减少,有效应力的增加,围岩的位移量急剧增加直至发生破坏。因此,对于本隧道而言,降雨是导致塌方的主要原因。
The entrance of Jiangyuanling tunnel is shallow buried,the surrounding rock is mainly full^strongly weathered granite,and fracture development.Rainfall led to right tunnel collapse in Yk32＋366 section during the construction process.This article analyzed the seepage field、displacement field of surrounding rock and the force acting on the support structure,studied on the mechanism of collapse using FLAC3D based on the basis of accident causes.The results show that,under the condition of rainfall,pore-water pressure of surrounding rock increased,hydration weakening effects enhanced,the cohesion and internal friction angle of rock and soil lessened,and weakened the stability of surrounding rock.With the excavation of the tunnel,Pore-water seeped from the excavation surface,pore-water pressure of surrounding rock decreased,effective stress increased,sharp increased in surrounding rock displacement until a failure occurs.Therefore,rainfall is the main cause to lead to collapse for this tunnel.
出处
《公路工程》
北大核心
2012年第6期196-199,共4页
Highway Engineering
