Tunnels often unavoidably traverse unfavorable geological structures like faults and joints. These surrounding rock structures can typically be simplified as rock mass structures containing combined defects of holes and fissures. In order to study the whole fracture process of rocks with a hole and collinear hole edge fissures after hole reinforcement, indoor biaxial compression tests were conducted, including high-speed camera photography. Utilizing RFPA3D (Realistic Failure Process Analysis) numerical simulation and rock mechanics theory, the strain and stress field throughout the entire fracture process were analyzed to study the initiation and growth of cracks in the samples. The research shows that the reinforcement ring prevented the inner wall of the hole in the specimen from peeling and fracturing, contributing to the integrity of the hole. However, a shear fracture region can still be seen at the intersection of the hole and fissures. The failure of unreinforced specimens under biaxial compression is mainly due to the expansion of wing cracks and anti-wing cracks, while that of reinforced specimens is mainly due to the expansion of secondary shear cracks. Regardless of the type of fracture mode, crack initiation usually occurs at the outer end of the collinear fissure, specifically as a tensile crack. Sometimes, the process is also accompanied by the generation of multiple secondary shear cracks and tensile cracks at the tips, resulting in other final fracture mode. Strain concentration typically occurs at the collinear fissure’s tips and intersections of circular hole and fissures.

中文翻译：

---

刚性加固环交叉断层隧道简化实验室模型的断裂过程：实验和数值见解


隧道通常不可避免地会穿过不利的地质结构，如断层和节理。这些围岩结构通常可以简化为包含孔洞和裂缝组合缺陷的岩体结构。为研究有孔岩石和加固后共线孔缘裂缝的整个断裂过程，进行了室内双轴压缩试验，包括高速相机摄影。利用 RFPA3D（真实失效过程分析）数值模拟和岩石力学理论，分析了整个断裂过程中的应变和应力场，以研究样品中裂纹的萌生和扩展。研究表明，加固环防止了试件中孔的内壁剥落和破裂，有助于孔的完整性。然而，在孔和裂缝的交点处仍然可以看到剪切断裂区域。未筋试件在双轴受压作用下的破坏主要是由于翼裂纹和反翼裂纹的扩大，而受筋试件的破坏主要是由于次生剪切裂纹的扩大。无论断裂模式的类型如何，裂纹萌生通常发生在共线裂缝的外端，特别是拉伸裂纹。有时，该过程还伴随着尖端处多个次生剪切裂纹和拉伸裂纹的产生，从而导致其他最终断裂模式。应变集中通常发生在共线裂缝的尖端以及圆孔和裂缝的交点处。