Study on the Evolution of Rock Fracture under True Triaxial Intermediate Principal Stress

作者：Zhaolin Li, Lianguo Wang, Lei Wang, Hao Fan, Bo Ren, Ke Ding · 发表于：International Journal of Geomechanics · 年份：2023 · DOI：10.1061/ijgnai.gmeng-7878 · 被引用次数：17 · 研究领域：Rock Mechanics and Modeling、Hydraulic Fracturing and Reservoir Analysis、Drilling and Well Engineering

An investigation of rock fracture characteristics subjected to the true triaxial intermediate principal stress is crucial for understanding the failure mechanism of surrounding rock in an actual underground engineering project and guiding the project’s implementation. In this study, a series of different true triaxial stress path tests were conducted to investigate the distribution of macroscopic rock fractures and internal cracks under various stress paths using a true triaxial servo test system and combining it with CT scanning technology. The results indicated that, due to the intermediate principal stress with constant direction, the true triaxial stress path has obvious directionality compared to the regular triaxial rock macroscopic and internal fracture distribution law and the fracture planes are aligned along the σ2 direction. Once the direction of the intermediate principal stress changes, the corresponding crack propagation direction immediately reverses and expands along the new intermediate principal stress direction. The direction of rock fracture is strongly dependent on the state (direction) of the intermediate principal stress, i.e., the direction of σ2 plays a decisive role in the macroscopic rock fracture characteristics. Accordingly, the “effect of intermediate principal stress-induced rock fracture” was proposed in this study. Based on the results of the CT scans in which the fracture dip angle within the rock is approximately parallel to the σ2 direction...