围压下岩石破坏过程的离散元模拟  

Discrete Element Simulation of Rock Failure Proceed under Confining Pressure

作　　者：张田 李雪峰 徐月 ZHANG Tian;LI Xue-feng;XU Yue(Xuzhou Mining Business Group Co.,Ltd.,Xuzhou 221006,China;School of Electromechanical,China University of Mining and Technology,Xuzhou,221116,China)

机构地区：[1]徐州矿务集团有限公司,江苏徐州221006 [2]中国矿业大学机电学院,江苏徐州221116

出　　处：《煤矿开采》2018年第4期8-14,共7页Coal Mining Technology

摘　　要：采用离散元软件PFC2D对模拟岩样进行了双轴压缩模拟,从细观角度观察和分析了围压对岩石强度特征、变形特征和破坏形态的影响。研究结果表明:随围压增加,岩样的抗压强度呈线性增强,且符合库伦强度准则;岩样的初始破裂应力和裂损应力均随围压增大而线性增大,但与峰值抗压强度的比值接近常数;岩样的弹性模量亦随围压增大而增大,但在较高围压时趋于平稳;压缩过程岩样轴向峰值应变和径向峰值应变均随围压增大呈线性增大,轴向峰值应变的增加幅度更大,且在模拟围压范围内均出现了体积扩容现象;围压下岩样以剪切破坏为主,且随围压增大,岩样破坏模式由脆性向延性转变,但围压对破坏角的影响较小,符合库伦准则。Biaxial compression simulation for simulated rock sample was proceed with discrete element software PFC2 D,and influence that confining pressure to rock strength character,deformation and failure pattern was analyzed from microscopic angle. The results showed that with confining pressure increased,compressive strength of rock sample appeared as linear increased,and conformed to Mohr-Coulomb strength criterion,initial broken stress of rock sample and rhegma stress all appeared linear increased with confining pressure increased,but specific value that to peak compressive strength approached to constant,also elasticity modulus increased with confining pressure increased,but appeared as smooth and stability as higher confining pressure. Peak value strain along axial and radial direction all appeared linear increased with confining pressure increased during compressive proceed,but axial peak strain increased range was larger,and volume dilatancy all appeared during experiments,the main failure was shear failure,and with confining pressure increased,rock sample failure mode changed from brittleness to ductility,but confining pressure had little influence to failure angle,conformed to Mohr-Coulomb strength criterion.

关 键 词：围压 离散元法 双轴压缩 破坏特征 

分 类 号：TD313[矿业工程—矿井建设]