Abstract:
In 20102 working face of Shennanwa Coal Mine, a large amount of gas gushing from the adjacent layer to the working face causes gas over-limit and threatens the safety production of the mine. It is necessary to adopt high level drilling and extraction, and the target layer of drilling directly determines the effect of high level decompression and extraction. Through UDEC software, Mohr-Coulomb model was used to establish the model. Physical and mechanical parameters of 2# coal seam, roof and floor coal and rock were selected and monitoring points were set. Based on the analysis of rock displacement, stress, monitoring point displacement, open fracture and slip deformation, it is concluded that after mining of 2# coal seam, the maximum development height of the fracture zone is 43 m, and the vertical fracture development area is a parabola with downward opening. The development width of the ionospheric fracture is about 21 m, and the maximum width of the vertical fracture is about 53 m. Combined with the actual situation of the mine, it is suggested that the final hole of the high borehole is arranged from 20 m to 35 m perpendicular to the roof of the coal seam, and 15 m to 30 m from the wall of the coal shaft in the horizontal direction.