巷道围岩松动圈形成机理的动静力学解析  

Dynamic and static analysis of mechanism of loosen zone in surrounding rock of tunnels

作　　者：陈建功[1,2] 贺虎[1,2] 张永兴[1,2] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设与新技术教育部重点实验室(重庆大学),重庆400045

出　　处：《岩土工程学报》2011年第12期1964-1968,共5页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51027004);长江学者和创新团队发展计划项目(IRT1045)

摘　　要：考虑巷道围岩在开挖过程中的动静力作用,提出了围岩松动区包含破碎区和塑性软化区两个部分。首先在围岩的瞬间卸载所产生的动力作用下,巷道周边围岩产生张拉裂隙破坏区,随后在原岩应力的静压作用下,产生拉剪复合破坏形成破碎区。塑性软化区是在原岩应力的静压作用下,随围岩变形的增大逐渐形成的。同时,根据弹性力学知识,得到巷道围岩由于开挖扰动和原岩应力作用引起的弹性应力场和位移场,提出了破碎区半径的求解方法。根据破碎区围岩应力的分布及残余强度理论,得到破碎区对塑性软化区的支撑反力,再利用塑性区的应力计算公式,得到了确定围岩松动区半径的计算公式。通过实例计算与实际监测对比表明,松动区的半径与现场实际观测到的结果吻合的较好。Considering the dynamic and static actions on surrounding rock during excavation process,the loosen zone is divided into two parts,broken zone and plastic softening zone.The transient unloading in surrounding rock will induce dynamic action on the rock near cavern periphery,leading to tension crack zone.Then,under the static action with the original stress in rock,the tension crack zone tends to be broken zone because of tension failure and shear failure.Under the stactic action with the original stress in rock,the deformatiom increases and the plastic softening zone is formed.Based on the elastodynamics theory,the stress redistribution and displacement field in surrounding rock induced by excavation are determined.A method to detemine the radius of the broken zone is put forward.On the basis of stress distribution in broken zone and the residual strength theory,the supporting force that the broken zone acts on the plastic softening zone is deduced.By means of the formula for calculating the stress in the plastic zone,an equation to calculate the radius of looen zone is deduced.The calculated results are in conformity the in-situ monitoring with data.

关 键 词：巷道 松动圈 动力学 静力学 

分 类 号：TU45[建筑科学—岩土工程]