Abstract It is generally known that discontinuities have a remarkable influence on the mechanical behaviour of rock masses. To further understand the fracture mechanisms of jointed rock masses, substantial effort has been focused on the strength anisotropy and failure characteristics of rocks/rock-like specimens containing persistent joints with different geometric parameters. However, only a few laboratory tests have considered the failure mechanism of a rock mass with 3D joints, especially for non-persistent joints with different persistence levels. In the present work, experiments on cubic rock-like specimens containing non-persistent joints (in areal extent) subjected to uniaxial compression were conducted to further investigate the influence of the joint inclination (θ) and persistence (N) on the rock mechanical properties and failure characteristics. The strength of a 3D non-persistent jointed specimen is characterized by three stages as the joint inclination angle (θ) increases from 0° to 90°. The strength of jointed specimens decreases with increasing N for all θ values, with the highest strength obtained for N = 0.42 and the lowest strength recorded for N = 0.92. Based on CT scan results, four typical fracture modes were identified: splitting, splitting + sliding, sliding, and intact failure. Overall, as the joint inclination increases, the failure mode of the specimen transforms from splitting to sliding and then to the intact failure mode. However, with decreasing joint persistence, the failure modes of some specimens will change from sliding to mixed failure (splitting + sliding).

中文翻译：

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单轴加载下非持久节理类岩石试样的破坏机制：实验室测试

摘要 众所周知，不连续性对岩体的力学行为有显着影响。为了进一步了解节理岩体的断裂机制，大量工作集中在包含具有不同几何参数的持久节理的岩石/类岩石试样的强度各向异性和破坏特征上。然而，只有少数实验室测试考虑了具有 3D 节理的岩体的破坏机制，特别是对于具有不同持久性级别的非持久节理。在目前的工作中，为了进一步研究节理倾角（θ）和持久性（N）对岩石力学性能和破坏特征的影响，对包含非持久节理（在面积范围内）的立方岩石样试样进行了单轴压缩实验。当接头倾斜角 (θ) 从 0° 增加到 90° 时，3D 非持久接头试样的强度分为三个阶段。对于所有 θ 值，连接试样的强度随着 N 的增加而降低，最高强度为 N = 0.42，最低强度记录为 N = 0.92。根据CT扫描结果，识别出四种典型的断裂模式：劈裂、劈裂+滑动、滑动和完整破坏。总的来说，随着关节倾角的增加，试件的破坏模式由劈裂转变为滑动，再转变为完整破坏模式。然而，随着接缝持久性的降低，一些试件的破坏模式将从滑动破坏转变为混合破坏（劈裂+滑动）。