Numerical study of related factors affecting mechanical properties of fractured rock mass and its sensitivity analysis

For the deep underground engineering, the fractured surrounding rock mass is the primary cause of the deformation of the underground structure. In this paper, the mechanical behavior of fractured rock mass samples under the influence of different related factors is studied by PFC3D software. Then, the sensitivity of the related factors is studied through the grey correlation analysis. It was found that the mechanical properties of fractured rock are mainly dependent on the lithology and fracture degree of the rock mass, which are the primary related factors affecting the peak and residual strength of the fractured rock, while the direction of the fracture plane and pore volume are the secondary related factors affecting its mechanical properties. Finally, combined with actual engineering, the importance of primary related factors is verified by studying the stability of a roadway in one deep coal mine.