关键词: 岩石力学, 大理岩, 蠕变, 损伤, 颗粒流程序, 数值模拟

Abstract: Creep damage and fracture of rock are the main forms of rock creep effect. But the internal damage evolution process of rock is difficult to be observed directly. So, the particle flow code (PFC2D) is used to analyze the mesomechanism of creep damage and fracture for Jingping marble. Based on the laboratory test data, the particle flow stress corrosion model (PSC) is used to establish the numerical model of Jinping marble. The model can simulate the short-term and long-term strength characteristics of Jinping marble. The numerical simulation result shows that the creep damage evolution process is significant different from the process in transient state. In the creep damage evolution process, the microcracks almost dehisce along the load direction; and the distribution of them is even. The number of microcracks in rock specimen increases rapidly firstly, and then increases stably. Finally, the microcracks evolution unstably till the rock sample fracture. When the load is lower, the rock specimens present the splitting failure state. However, when the load is higher, the rock specimens present the shear failure state. In the initial damage stage and prophase of stable evolution stage, the load magnitude has a little effect on the creep damage process of rock specimens. In the later stage of stable evolution stage and the failure stage, the damage of rock specimens under lower load increases faster than the specimens under higher load.

Key words: rock mechanics, marble, creep, damage, particle flow code, numerical simulation