复合岩层强度特性及破坏机理三轴加载试验研究  

Triaxial loading test of strength behavior and failure mechanism of composite rock

作　　者：程建龙 罗松[3] 李佳宝 李劲锋 刘浩 杨圣奇[2] 赵维生[4] CHENG Jianlong;LUO Song;LI Jiabao;LI Jinfeng;LIU Hao;YANG Shengqi;ZHAO Weisheng(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Guiding CONCH Panjiang Cement Co Ltd,Guiding,Guizhou 551300,China;Institute of Mining Engineering,Guizhou Institute of Technology,Guiyang,Guizhou 550003,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [2]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 [3]贵定海螺盘江水泥有限责任公司,贵州贵定551300 [4]贵州理工学院矿业工程学院,贵州贵阳550003

出　　处：《采矿与安全工程学报》2020年第6期1246-1254,共9页Journal of Mining & Safety Engineering

基　　金：国家重点基础研究发展计划项目(2014CB046905);贵州省科技计划项目(黔科合支撑〔2019〕2882号);贵州省教育厅青年科技人才成长项目(黔教合KY字〔2017〕219)。

摘　　要：对不同倾角复合岩层试样进行了常规三轴抗压试验,研究了层理倾角和围压对复合岩层试样峰值强度的影响规律,探讨了复合岩层试样强度的各向异性特征,深入分析了不同围压下试样的破坏模式,揭示了软硬岩层基质和层理面活化裂纹方向及数量统计特征,明确了复合岩层在三轴加载过程中的破坏机理。得出在θ从0°增加至90°过程中,黏聚力先降低后升高并在θ=60°取得最小值,其变化规律与峰值强度的变化规律基本一致,而内摩擦角总体呈现降低趋势。θ=0°~90°试样的峰值强度随围压升高强度各向异性比降低,且θ=0°和θ=90°试样的峰值强度随围压升高逐渐趋于相等。低围压下θ=0°~30°试样在加载过程中软岩发生剪切破坏,裂纹方向多与加载方向有一夹角,而硬岩发生张拉劈裂破坏,裂纹方向大多平行于加载方向且大致呈正态分布。硬岩基质中的间断裂纹数量随围压升高逐渐减少。Conventional triaxial compression tests have been conducted on composite rock specimens with different dip angles.The effect of bedding dip angle and confining pressure on the peak strength of the composite rock samples has been studied,the anisotropy of strength behavior of the samples has been discussed,the failure mode of specimen under different confining pressure has been deeply analyzed,the direction and quality of fractures occurred in weak and hard rock martrix and bedding plane have been revealed,and therefore,the failure mechanism of composite rock has been clarified in the triaxial loading test.The results have shown that the cohesion first decreases to a minimum atθ=60°,and then increases in the process ofθincreasing from 0°to 90°.The change law is basically consistent with that of peak strength.But the internal friction angle presents a decreasing trend.The anisotropy ratio of peak strength decreases and the strength for the specimens(θ=0°andθ=90°)trend to equalize with the increasing confining pressure.Under lower confining pressure,the specimens(θ=0°-30°)is subjected to shear failure in weak rock layers and there is an angle between fracture direction and the loading direction.However,tensile splitting failure occurs in the hard rock layers and the crack direction is mostly parallel to the loading direction and generally normally distributed.The number of intermittent cracks in hard rock matrix decreases gradually with the increase of confining pressure.

关 键 词：复合岩层 三轴抗压试验 强度特性 破坏机理 裂纹特征 

分 类 号：TD313[矿业工程—矿井建设]