To analyze the fault slip mechanism under static and cyclic disturbance loads during construction, a series of true triaxial monotonic and cyclic loading tests on rough fractured granite were conducted. The effects of confining pressure and loading path on the slip characteristics of fractured granite with a 60° fracture angle were explored. Based on stress, strain monitoring, and acoustic emission techniques, the shear stress, shear displacement, friction coefficient, and energy release process during the fracture slip of fractured granite were analyzed. Meanwhile, macroscopic and microscopic observations were made to examine the morphological evolution of the fracture surface before and after slip. The results show that confining pressure is a key factor that limits the fracture slip of fractured granite. Compared to the intermediate principal stress, the increase in the minimum principal stress has a more significant effect on the increase in the peak shear stress of the fractured granite. Under true triaxial cyclic loading, the peak strength, shear stress, and static friction coefficient of fractured granite are higher than those under monotonic loading. As the confining pressure increases, the precursor AE characteristics of fractured granite specimens before slip become more pronounced. During the frictional sliding of the fracture surface, asperities on the surface are compressed and ground in the form of transgranular cracks, and both the roughness and the fractal dimension decrease. Compared with monotonic loading, under true triaxial cyclic loading, the fracture surface and the surrounding rock matrix are severely damaged after fracture slip, and transgranular and intergranular cracks develop. The debris and powder produced by fracture slip form fault gouge, which adheres to the fracture surface and accumulates in micro-pores and micro-cracks.

中文翻译：

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真三轴单调和循环荷载作用下粗糙断裂花岗岩剪切行为的试验研究

为分析施工过程中静力和循环扰动载荷作用下的断层滑移机理，对粗糙裂隙花岗岩进行了一系列真三轴单调和循环载荷试验。探究围压和加载路径对 60° 断裂角裂隙花岗岩滑移特性的影响。基于应力、应变监测和声发射技术，分析了碎隙花岗岩裂隙滑移过程中的剪切应力、剪切位移、摩擦系数和能量释放过程。同时，通过宏观和微观观察观察，观察滑移前后裂缝表面的形态演变。结果表明：围压是限制碎隙花岗岩裂缝滑移的关键因素;与中间主应力相比，最小主应力的增加对裂隙花岗岩峰值剪应力的增加具有更显著的影响。在真三轴循环载荷下，裂隙花岗岩的峰值强度、剪应力和静摩擦系数均高于单调载荷下。随着围压的增加，裂隙花岗岩试件在滑移前的前驱体 AE 特性变得更加明显。在裂隙表面的摩擦滑动过程中，表面的凹凸不平被压缩并以跨晶裂纹的形式研磨，粗糙度和分形维数均减小。与单调加载相比，在真正的三轴循环加载下，裂缝滑移后裂缝表面和围岩基质受到严重破坏，出现跨晶裂和晶间裂缝。 裂缝滑移产生的碎屑和粉末形成断层凿痕，粘附在裂缝表面并积聚在微孔和微裂纹中。