Numerical study on the influence of fault orientation on risk level of fault slip burst disasters in coal mines: a quantitative evaluation model

The orientation of the fault is significant for interpreting the stress and energy fields of fault pillars and explaining the occurrence of rockburst. However, current risk assessment methods for rockburst do not fully consider the role that fault orientation plays in varying the risk level of working faces. In this paper, we explore the effect of the fault dip angle (θ), fault strike (φ), the width of the fault zone (d), and the distance between the working face and the fault (l) on the temporal and spatial evolution of stress and elastic energy. We determine the weight index of fault orientation on the risk of the working face using the AHP method. Then, we build a quantitative evaluation model to perform risk assessment and evaluation of the fault pillar instability in coal mines. The results show that when the fault dip angle is 75°, the fault strike is 50°, and the fault zone width is 6 m, the risk level of the 5366 working face of Hengda coal mine is the highest. Finally, we apply the evaluation method to Dongtan coal mine, Qianqiu coal mine, and others for verification. The study achievements can supply theoretical support for revealing the stress and energy fields, risk assessment in the fault mining area, and research on the evolutional mechanism of fault slip burst.