摘要
针对不同连接率断续节理岩体,基于PFC^2D颗粒流程序在不同法向应力下进行直剪试验,研究其剪切破坏过程及强度特性。数值模拟结果表明:断续岩桥的贯通破坏过程具有明显的阶段性,可根据剪切应力曲线以及微观裂纹扩展特征将其大体分为4个阶段;断续岩桥的初裂强度和剪切峰值强度与法向应力成正相关而与节理连通率成负相关,初裂强度百分比对法向应力变化不敏感而随着节理连通率的增加而增加;岩体内部能量的演化过程能较好的匹配断续岩桥的贯通破坏过程,可将应变能、耗散能的突变点作为断续岩桥贯通破坏的标志,耗散能对法向应力的变化较节理连通率更为敏感。
According to the discontinuous jointed rock masses with different connection rates, PFC2 D was used to conduct direct shear tests under different normal stresses in order to analyze the shear failure process and strength characteristics. The numerical simulation results show that the breaking process of discontinuous rock bridge has distinct stages, which can be roughly divided into four stages according to the shear stress curve and the microscopic crack growth characteristics. The initial crack strength and shear peak strength of discontinuous rock bridge are positively correlated with normal stress and negatively correlated with joint connectivity. The percentage of initial crack strength is not sensitive to normal stress change, but increases with the increase of joint connectivity. The breaking through failure process of discontinuous rock bridge can be well matched by the evolution process of internal energy of rock mass, and the break point of strain energy and dissipation energy can be taken as the mark of breaking through failure of discontinuous rock bridge, moreover, dissipated energy is more sensitive to the change of normal stress than the connectivity of joints.
作者
王雅婷
崔精
WANG Yating;CUI Jing(China Interchange Second High way Survey Design Research Institute Co.,Ltd.,Wuhan,Hubei 430056,China)
出处
《水利与建筑工程学报》
2019年第5期234-238,共5页
Journal of Water Resources and Architectural Engineering
关键词
断续节理岩体
岩桥
剪切强度
能量演化
discontinuous jointed rock mass
rock bridges
direct shear strength
energy evolution
