Simulation study on influencing factors of coal wall sudden extrusion in heading face

A three-dimensional numerical model of heading face was established based on Guoerzhuang Coal Mine in Handan, Hebei Province. The effects of different coal seam depths, driving speed and coal mechanical strength on the coal wall sudden extrusion are analyzed by using 3DEC discrete element simulation software, and the orthogonal experiment method is used to rank the influencing factors according to the degree of importance. The results show that there is a positive linear correlation between the maximum horizontal displacement of the fixed point on the heading face and the change of the buried depth, and the direction of the coal wall extrusion displacement is close to the central axis of the roadway, and the horizontal displacement is obviously larger than the vertical displacement. Under the condition of the buried depth of 600 to 1 000 meters, the width of stress concentration area of working face is about 10 meters, and the position of the stress peak is about 5 meters from the working face. The factors affecting the coal wall sudden extrusion in heading face are in the following order: buried depth of coal seam > driving speed > mechanical strength of coal body. The research results provide a reference for further understanding of the coal wall sudden extrusion and preventive measures.