The research on mechanism and prevention strategy of coal and gas outburst in normal faults based on support body model

The depth of coal mining in China is increasing year by year, and the coal and gas outburst is becoming more and more serious. Most of the coal and gas outburst sites occur in normal faults. In this paper, the evolution law of stress and displacement field of workface under different tectonic zone width of the normal fault was studied, and the support body model of normal fault was constructed, the occurrence mechanism of normal fault coal and gas outburst was revealed, and the prevention and normal fault control strategy was put forwarded. The results show that the greater the width of the fault tectonic zone, the higher the horizontal stress of the driving face, the greater the deformation degree, and the higher the risk of coal and gas outburst. The criterion of coal and gas outburst induced by disturbance of normal fault was proposed, and the evolution process of coal and gas outburst from start to end of normal fault is revealed. Using the microseismic and electromagnetic radiation to monitor the normal fault area, it is found that the fracture frequency and stress of coal rock in the normal fault area are significantly higher than those in the non-fault area. The prevention and control of coal and gas outburst in normal fault should be started from two aspects: eliminating the energy and improving the supporting ability of tectonic zone. The research results provide a new strategy for the prevention and control of coal and gas outburst in fault zones.