岩石内部微裂隙的起裂贯通破坏易引发边坡滑坡、隧道塌方和采场冒顶等工程事故，造成巨大的经济损失和恶劣的社会影响。为了探究裂隙岩石中裂隙演化规律及破坏机理，根据相似理论，采用细沙、白水泥和水按一定比例制作含十字交叉裂隙的类岩石试样，利用RMT-150B岩石力学试验机对其进行单轴压缩试验，并基于室内试验测试结果，建立了含预制十字交叉裂隙岩石试样的PFC数值模拟模型，分析含十字交叉裂隙试样的裂纹起裂、扩展和贯通的演化规律及其失稳破坏机理。研究结果表明：含十字交叉裂隙试样的峰值强度和弹性模量低于完整试样；数值模拟结果的峰值强度、弹性模量、起裂应力和裂隙倾角的变化关系与室内试验测试结果的变化关系基本吻合，即随着裂隙倾角的增大呈现先增大后减小的倒“V”形变化趋势；裂隙倾角为0°时微裂纹起裂于主次裂隙尖端，裂隙倾角为30°时裂纹起裂于主裂隙尖端，裂隙倾角为45°和60°时裂纹起裂于次裂隙尖端；微裂纹数量随应变增加经历了静止期、增加缓慢期、中期增加期和最活跃期4个阶段，且后一阶段增长率总是高于前一阶段；裂隙倾角为0°、30°、45°和60°时试样的破坏模式均为对角剪切破坏。

Defects in rocks make their physical properties anisotropic.When subjected to external force，the defect will crack，expand and even destroy.Therefore，it is very important to study its failure behavior to predict the instability of engineering structure.Previous studies are more concentrated on the evolution process of single fracture or non intersecting multi fracture，however，rock fracture often exists in the form of intersecting multi fracture in practical engineering.Based on RMT-150B，the cross fracture rock samples （150 mm×200 mm×45 mm） with different fracture inclination were prepared in the laboratory，and the uniaxial compression test was carried out with the displacement controlled loading mode of 0.01 mm/s.The results show that the peak strength and modulus of elasticity of the cross fracture specimen are lower than that of the intact specimen.The peak strength，modulus of elasticity and crack initiation stress increase first and then decrease with the increase of fracture inclination.In order to make up for the shortcomings of laboratory test technology in reflecting the macro and micro morphology of cross cracks，PFC^2D numerical simulation technology was used to calibrate the micro parameters of the numerical model by comparing the deformation and failure characteristics of the complete specimen.The results of numerical simulation show that the relationship between peak strength，modulus of elasticity，initial crack stress and crack inclination is basically consistent with the results of laboratory tests.From the process of crack evolution，it is observed that the inclination angle of 0° is the simultaneous cracking from the tip of the primary and secondary cracks，the inclination angle of 30° is the crack initiation from the tip of the primary crack，and the inclination angle of 45° and 60° are the cracks from the tip of the secondary crack.The number curves of microcracks are divided into four stages，namely quiescent period, slow increase period, mid-term increase period, and most active period，and the growth rate of the latter stage is always higher than that of the former stage，the change characteristics of cracks are different in different stages.It can be clearly seen from the displacement field that when the inclination angles are 0°，30° and 45°respectively，the specimen is the diagonal shear failure controlled by the secondary fracture.When the inclination angle is 60°，the specimen is mainly the shear failure controlled by the main fracture.

http://www.goldsci.ac.cn/article/2020/1005-2518/1005-2518-2020-28-4-509.shtml