College of Architecture and Engineering, Liaocheng University, Liaocheng, Shandong Province, China.
PLoS One. 2024 Nov 14;19(11):e0312344. doi: 10.1371/journal.pone.0312344. eCollection 2024.
A large number of joints and fissures are prevalent in the rock mass, which has an important influence on the mechanical properties of the rock mass. To study the failure mechanical characteristics of Y-cracked rocks, the paper analyzes the influence of different angles of prefabricated Y-cracked rocks on the mechanical strength characteristics of the rocks and the crack extension evolution through uniaxial compression indoor tests and discrete element PFC2D numerical simulation. The results indicate that the stress-strain curves of rocks containing prefabricated cracks exhibit five stages: the initial pore-fracture compaction stage, the elastic stage, the crack stable development stage, the crack unstable development stage, and the post-peak rupture. The peak strength of the specimen shows an evolutionary process of decreasing, then increasing, and then decreasing with the increase of the Y-shaped crack angle. The failure of the sample is mainly caused by the shear crack expansion at the crack tip. The different Angle cracks directly affect the mechanical properties of the sample and the generation and evolution of new cracks. The final failure of rock is mainly the result of microcrack propagation, convergence and penetration to form macroscopic damage zone. Finally, combined with PFC numerical simulation, the distribution of micro-cracks and the damage pattern of rock damage are compared and analyzed, and it is found that the two are in good agreement, which reflects the rationality of the model.
大量节理和裂隙普遍存在于岩体中，这对岩体的力学性质有重要影响。为研究含 Y 型裂隙岩石的破坏力学特性，本文通过室内单轴压缩试验和离散元 PFC2D 数值模拟，分析了预制 Y 型裂隙不同角度对岩石力学强度特性及裂隙扩展演化的影响。结果表明，含预制裂隙岩石的应力-应变曲线呈现五个阶段：初始孔隙-裂隙压密阶段、弹性阶段、裂隙稳定扩展阶段、裂隙非稳定扩展阶段和峰后破裂阶段。试件的峰值强度随着 Y 型裂隙角度的增加呈现先减小后增大再减小的演化过程。试件的破坏主要是由裂隙尖端的剪切裂纹扩展引起的。不同角度的裂隙直接影响试样的力学性能以及新裂隙的产生和演化。岩石的最终破坏主要是微裂纹扩展、收敛和穿透形成宏观损伤带的结果。最后，结合 PFC 数值模拟，对比分析了微裂纹的分布和岩石损伤的破坏模式，发现两者吻合较好，反映了模型的合理性。
