基于Mohr-Coulomb准则的球形洞室围岩应变软化弹塑性分析  

Elastoplastic analysis of spherical cavity in strain-softening rock masses based on Mohr-Coulomb criterion

作　　者：冯强[1] 范金成[2] 张强[1,2] 蒋斌松[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]中国矿业大学力学与建筑工程学院,江苏徐州221116

出　　处：《煤炭学报》2014年第5期836-840,共5页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(51174196;51204168)

摘　　要：通过用一系列的塑性流动与脆性跌落近似逼近峰后应变软化过程,将开挖球形洞室引起的塑性变形区划分为k个同心球壳。假定各球壳内岩体均质且各向同性,采用Mohr-Coulomb准则和非关联流动法则对受静水压力球形洞室围岩的应力和变形进行理论计算。由各球壳内岩体属性表征点建立岩体再破坏的补充方程,得到了围岩塑性半径求解方程组。通过算例验证了方法的合理性。最后,考虑岩体进入峰后阶段后,变形参数也随之劣化,讨论了弹性模量线性劣化对洞壁位移、软化半径和破裂半径的影响。The strain-softening process of rock media after peak-load was simplified into a series of plastic flows and brittle falls. The plastic deformation region caused by the excavation of a spherical cavity was divided into several con- centric spherical rings. Assumed that in each spherical ring the rock masses were infinitely homogeneous and isotropic. Based on Mohr-Coulomb criterion and non-associated flow rule, the closed-form solutions of stresses and displacements around the spherical cavity subjected to hydrostatic initial stresses were obtained. Through the characteristic point of material properties in each spherical ring, supplementary equations of rock media to be destroyed were presented and the iterative formulas of plastic radii were also obtained. Considering that deformation parameters of the surrounding rock mass deteriorate after peak-load, this paper respectively discussed the effects of the linear degradation of the elastic modulus and Poisson＇ s ratio on the displacement of free surface, softening radius and rupture radius.

关 键 词：球形洞室 应变软化 弹塑性分析 MOHR-COULOMB准则 静水压力 变形模量劣化 

分 类 号：TD313[矿业工程—矿井建设]