The initiation, propagation, and coalescence of cracks in the rock bridge are the root causes of rock failure. However, the identification of cracks propagation paths is a problem in rock mechanics. This paper studies the evolutionary law of the strain field in the rock bridge region of granite with pre‐fissures using 3D‐DIC after equivalence and simplification. Based on the real crack initiation mechanism of “relative slip between regions” proposed in this paper, combined with the priority order of crack propagation at the edge of the rock bridge, the pattern of cracks propagation and coalescence was obtained. We analyze the fracture characteristics in roughness and morphology to verify the validity of the proposed mechanism. The tensile and shear failure areas around the rock bridge were identified quantitatively, and the roughness, fractal dimension, and energy consumption of the sections formed by tensile failure and shear failure are different.

中文翻译：

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基于DIC和激光扫描技术研究预制裂缝花岗岩的断裂行为

岩石桥梁中裂缝的产生，传播和合并是岩石破坏的根本原因。然而，裂缝传播路径的识别是岩石力学中的一个问题。经过等价和简化后，本文利用3D-DIC研究了具有预裂隙的花岗岩岩桥区域应变场的演化规律。基于本文提出的“区域间相对滑动”的真实裂纹萌生机理，结合岩桥边缘裂纹扩展的优先顺序，得出了裂纹扩展和聚结的规律。我们分析了粗糙度和形态的断裂特征，以验证所提出机制的有效性。定量确定了岩桥周围的拉伸和剪切破坏区域，并确定了粗糙度，