初始裂隙倾角对岩石损伤断裂特征的影响研究

Study on influence of initial crack dip angle on damage-fractured characteristics of rock

为了探求初始裂隙倾角对岩石损伤裂断特征的影响,采用岩石破裂过程的RFPA数值分析系统,对单轴压缩作用下的不同裂隙倾角的单裂隙试件破坏过程进行数值模拟。根据获得的不同加载步的岩石内部应力图像,分析初始裂隙倾角对岩石裂隙扩展方向及试件断裂方向的影响,获得了岩石内部应力再分布规律,结合声发射累积事故数随加载步的变化,将岩石内部应力分为损伤产生并稳定扩展阶段、损伤快速扩展并连通阶段和岩石破坏阶段。研究结果表明:在损伤产生并稳定扩展阶段,岩石内部的应力最大值随加载步的增加基本按线性增加,且初始裂隙倾角为45°时最大主应力和最大剪应力的最大值增长最快,初始裂隙倾角为15°时最小主应力的最大值增长最快。

In order to discuss on impacts of initial crack dip angle on damage-fractured characteristics of rock,the damage-fractured process of rock with a single crack under uniaxial compression was simulated using numerical test of rock failure RFPA. Five samples with different crack dip angle were used. The influence of initial crack dip angle on crack propagation direction and fracture direction in rock was analyzed according to stress images of different loading steps. Redistribution laws of internal stress of rock were obtained. It was divided into three stages such as damage initiation and stable growth stage,damage rapid expansion and connection stage and rock failure stage with the change of AE count. Results showed that stress values in rock increased linearly on the stage of damage initiation and stable growth. The maximum values of maximum principal stress and maximum shear stress increased most rapidly when the initial crack dip angle was 45°. The maximum value of minimum principal stress increased most rapidly when the initial crack dip angle was 15°.