Abstract Shear failure of rock masses along discontinuities is one of the dominant failure modes of underground tunnels and rock slopes. In this paper, the shear fracture evolution and failure mechanism of rock-like materials containing cross-flaws are first reported based on a developed CZM-FEM method. The laboratory uniaxial compression and corresponding numerical tests were initially performed to acquire the mechanical parameters of rock-like materials. Subsequently, the direct shear test of rock-like materials containing two sets of cross-flaws was conducted, the effect of the main flaw and secondary flaw angles were considered. At last, the mechanical properties and fracture behaviors, and the coalescence mechanism were investigated and concluded. The results indicate that four typical stages are observed during the shearing process of rock-like materials with cross-flaws, which are the linear elastic stage, crack strengthening stage, plastic softening stage, and residual strength stage, respectively. Note that the mechanical properties (i.e., peak, residual shear strength, and the crack initiation stress) and cracking behaviors are strongly dependent on the angles of the main and secondary flaws as well as the loading conditions (i.e., shear rates and constant applied normal stresses). In addition, the coalescence mechanism of rock bridge between the two cross-flaws can be classified into three types, which are the mixed shear tensile-tensile damage, shear-tensile damage, and tensile damage, respectively; Similarly, the coalescence paths can also be identified as three types, respectively, the connection between the main flaw and the secondary flaw, linkage by the two secondary flaws, and the penetration dominated by the main flaw and the secondary flaw.

中文翻译：

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剪切作用下含横向裂纹类岩石材料的断裂演化及破坏机制

摘要 岩体沿不连续面的剪切破坏是地下隧道和岩质边坡的主要破坏模式之一。在本文中，基于开发的 CZM-FEM 方法首次报道了含有横向缺陷的类岩石材料的剪切断裂演化和破坏机制。初步进行了实验室单轴压缩和相应的数值试验，以获得类岩石材料的力学参数。随后，对含有两组横向缺陷的类岩石材料进行了直剪试验，考虑了主缺陷和次要缺陷角度的影响。最后，对力学性能和断裂行为以及聚结机理进行了研究和总结。结果表明，在具有横向缺陷的类岩石材料剪切过程中观察到四个典型阶段，分别是线弹性阶段、裂纹强化阶段、塑性软化阶段和残余强度阶段。请注意，机械性能（即峰值、残余剪切强度和裂纹起始应力）和开裂行为强烈依赖于主要和次要缺陷的角度以及加载条件（即剪切速率和恒定应用法向）应力）。此外，两种横向裂缝间岩桥的聚结机制可分为三种类型，分别为剪切拉拉混合损伤、剪切拉拉损伤和拉拉损伤；类似地，聚结路径也可以分别识别为三种类型，