真三轴应力作用下立方体节理煤岩力学响应试验研究

To investigate the influence of the intermediate stress and bedding plane on the jointed coal masses under the true triaxial stress state, the true triaxial compression experiments were performed on the jointed coal masses with respect to the following two loading conditions, the intermediate principal stress direction parallel to and perpendicular to the beddings plane direction. According to the experimental results, the failure strength as well as deformation of the jointed coal masses were studied considering the bedding plane and stress effects. The complex failure patterns of the jointed coal masses were discussed through the three dimensional limited Mohr circle approach. The results show that at the same minimum principal stress, the ultimate strength of jointed coal mass increases with the increasing intermediate principal stress; The relative orientation between the intermediate principal stress and bedding planes has a remarkable influence on the deformation and strength of the jointed coal masses. When the intermediate principal stress direction is perpendicular to the bedding planes, the jointed coal masses are hard to break, whereas the deformation is limited in the direction of the minimum principal stress. Mogi criterion agrees well with the jointed coal masses under the true triaxial loading condition, especially when the intermediate principal stress direction parallel to the bedding plane direction.