考虑刚度与强度劣化的洞室围岩弹塑性分析

Elastoplastic analysis of surrounding rock of caverns considering deterioration of stiffness and strength

地下洞室锚固围岩进入塑性状态后其刚度与强度均会产生一定程度的劣化。将锚固围岩视为复合岩体并借助参数等效原则求出其刚度与强度参数后,基于D-P屈服准则得到了考虑劣化效应的深埋圆形洞室锚固围岩弹塑性解,借助FLAC-3D有限差分软件验证了该方法的可靠性后对相关影响因素进行了具体分析。研究结果表明:①考虑锚固围岩的刚度与强度同时劣化后得到的围岩变形量更符合实际;②残余黏聚力c"、残余内摩擦角φ"、残余弹性模量E"的大小对锚固塑性残余区半径Rb、洞壁位移u具有控制性作用,当c",φ",E"取值越大时,Rb,u便会越小,反之Rp、Rb、u便会越大;③软化模量Mc、Mφ对塑性残余区半径Rb、洞壁位移u的影响较大,对塑性软化区半径Rp的影响可以忽略;④系统锚杆与支护阻力pi协调作用下可以有效控制塑性残余区范围及围岩变形。

The stiffness and strength of the surrounding rock in underground caverns will deteriorate to a certain extent when it enters the plastic state.Based on the D-P yield criterion,the elastic-plastic solution for the anchored surrounding rock of deep-buried circular caverns is obtained considering the deterioration effects.The reliability of the method is verified by using the FLAC3D finite difference software,and the relevant influencing factors are analyzed.The results show that:(1)Considering the deterioration of the stiffness and strength of the anchored surrounding rock,the deformation of the surrounding rock is more realistic.(2)The residual cohesion c,the residual internal friction angleφ,the residual elastic modulus E have controlling effects on the anchorage plastic residual zone radius Rb and the wall displacement u.The larger the values of c,φ,E,the smaller the values of Rb and u,and vice versa.(3)The softening moduli Mc and Mφhave great influences on the radius Rb of the plastic residual zone and the wall displacement u,but the influences on the radius Rp of the plastic softening zone can be ignored.(4)Under the coordinated action of system bolt and support resistance pi,the scope of the plastic residual zone and the deformation of the surrounding rock can be effectively controlled.