The instability of rock slopes and underground engineering structures is usually caused by shear sliding along discontinuities, such as joints or faults, which are usually non-persistent. It is important to study the shear failure behavior of non-persistent joints to better understand the instability mechanism of jointed rock masses. In this research, rock-like samples containing multiple non-persistent joints were prepared and used for direct shear tests under constant normal load. The test results showed that the shear failure of multiple non-persistent joints usually involves multiple coalescence modes of rock bridges, which are affected by joint configurations and normal stress. Under the same normal stress, the shear strength, and dilation behavior are mostly dominated by joint persistency, which essentially determines the roughness of the macroshear fracture surface. Furthermore, the acoustic emission characteristics of non-persistent joints were evaluated by the hit rate, energy rate, and b value. A lower b value, indicating a more intense shear failure, is usually related to a smaller joint persistency and medium joint spacing. Finally, the cracking process, force evolution, and micro-cracking mechanism of multiple non-persistent joints were revealed using particle flow code.

中文翻译：

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含多个非持久节理的类岩石样品剪切破坏行为的实验和数值研究

岩石边坡和地下工程结构的失稳通常是由沿不连续性的剪切滑动引起的，例如节理或断层，这些不连续性通常是非持久性的。研究非持久节理的剪切破坏行为对于更好地理解节理岩体的失稳机制非常重要。在这项研究中，制备了含有多个非持久节理的类岩石样品，并用于在恒定法向载荷下进行直剪试验。试验结果表明，多个非持久节理的剪切破坏通常涉及岩桥的多种聚结模式，受节理配置和正应力的影响。在相同的法向应力下，剪切强度和膨胀行为大多以关节持久性为主，这实质上决定了宏观剪切断裂表面的粗糙度。此外，非持久关节的声发射特性通过命中率、能量率和b值进行评估。较低的 b 值表明更强烈的剪切破坏，通常与较小的接缝持久性和中等接缝间距有关。最后，使用粒子流代码揭示了多个非持久接头的开裂过程、力演化和微开裂机制。