Abstract The failure and mechanical behavior of transversely isotropic rock are significantly affected by the original bedding planes. Until now, few studies have been performed to investigate the influence of the geometrical and mechanical parameters of the bedding planes on the fracture characteristics of transversely isotropic rocks under planar shear fracture loading conditions. For this purpose, experimental and numerical compression-shear tests on double-notched specimens are conducted to investigate the fracturing characteristics of transversely isotropic rock under planar shear fracture loading. The experimental study that focuses on the influence of bedding plane inclination on fracture load, fracture pattern and AE evolution, and six inclination angles is conducted in this study. Based on the flat joint contact model (for the rock matrix) and smooth joint contact model (for the original bedding plane) in PFC2D (particle flow code), the microscale fracturing process of transversely isotropic rock with different inclinations is simulated and analyzed. The results show that the inclination has an important influence on the fracture load and fracture pattern, and the maximum and minimum fracture loads are obtained for specimens with inclination angles of 30° and 60°, respectively. Moreover, the strength and spacing of the original bedding planes also play an important role in fracture loads. Higher bedding plane strength and wider bedding plane spacing result in higher fracture loads. In addition, with a moderate inclination angle, transversely isotropic rock with higher bedding plane strength tends to form cracks that cut through the rock matrix. However, with the decrease in the bedding plane strength, more fractures form along the bedding planes.

中文翻译：

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压缩剪切试验下横向各向同性岩石的破坏和力学行为：实验室测试和数值模拟

摘要 横向各向同性岩石的破坏和力学行为受原始层理面的影响很大。迄今为止，在平面剪切断裂载荷条件下，研究层理面的几何和力学参数对横向各向同性岩石断裂特征的影响的研究很少。为此，对双缺口试样进行了实验和数值压缩-剪切试验，以研究横向各向同性岩石在平面剪切断裂载荷下的断裂特性。本研究以层理面倾角对裂缝载荷、裂缝模式和声发射演化的影响为重点，进行了6个倾角的试验研究。基于PFC2D（粒子流代码）中的平节理接触模型（针对岩石基体）和平滑节理接触模型（针对原始层理面），模拟分析了不同倾角横向各向同性岩石的微尺度压裂过程。结果表明，倾角对断裂载荷和断裂方式有重要影响，分别获得了倾角为30°和60°的试件的最大和最小断裂载荷。此外，原始层理平面的强度和间距在断裂载荷中也起着重要作用。更高的层理面强度和更宽的层理面间距导致更高的断裂载荷。此外，以适度的倾斜角度，具有较高层理面强度的横向各向同性岩石往往会形成穿透岩石基质的裂缝。然而，随着层理面强度的降低，沿层理面形成更多的裂缝。