论文部分内容阅读
岩石的蠕变损伤和断裂是岩石流变效应的重要表现形式,但其损伤演化过程往往难以直观观测,为此,采用二维颗粒流数值模拟方法(PFC2D)对岩石的蠕变损伤和断裂的细观力学机制进行了分析。在锦屏大理岩室内试验基础上,利用颗粒流应力腐蚀模型(PSC),建立了能反映其短期和长期强度特征的柱状岩样数值模型,并开展了大量数值试验。结果表明,蠕变损伤的演化过程与暂态的损伤演化过程具有明显的差异。在岩样蠕变损伤过程中,其内部微裂纹多沿加载方向开裂且分布均匀,先快速增加再稳定扩展,最后则发生快速断裂。当荷载较小时,岩样宏观上呈现劈裂破坏特征,当荷载较大时,岩样呈现剪切破坏特征。在岩样蠕变损伤初始和稳定演化阶段的前期,荷载大小对岩样的损伤演化过程影响不大;在稳定演化阶段的后期至断裂过程中,低荷载下岩样的损伤增速比高荷载下快。
The creep damage and fracture of rock are the important manifestations of the rheological effect of rock, but the damage evolution process is often difficult to observe directly. Therefore, two-dimensional particle flow numerical simulation method (PFC2D) is used to study the creep damage and fracture of rock Meso-mechanics mechanism was analyzed. Based on the laboratory test of Jinping marble, a numerical model of columnar rock specimen that can reflect its short-term and long-term strength characteristics is established by particle flow stress corrosion model (PSC). A large number of numerical experiments are carried out. The results show that the evolution of creep damage and transient damage evolution have obvious differences. In the process of rock specimen creep damage, most of the internal micro-cracks were cracked and distributed evenly along the loading direction. The micro-cracks were rapidly increased and then stably expanded, and finally the rapid fracture occurred. When the load is small, the rock samples show the characteristics of splitting failure macroscopically. When the load is large, the samples show the characteristics of shear failure. In the early stage of rock creep damage initial and steady evolution stage, the load size has little effect on the rock damage evolution process. During the period from the late stage of stable evolution to fracture, the damage growth rate of rock specimen under low load is higher than that of high load Quickly.