Simulation study on gas control of hygraulic flushing in hole and drainage drilling in low permeability coal seam

In order to eliminate the outburst risk of Ji_15-16-24100 working face in the process of preparation and mining in Pingmei No. 10 Coal Mine, the gas control process of hygraulic flushing in hole combined with drainage drilling was studied by fine simulation. The interaction of gas desorption, seepage and coal-rock deformation was analyzed, and the stress-seepage coupling mathematical equation of gas migration in coal seam was constructed. Finite element software was used to solve it, and the whole process of mining of this coal seam was simulated by numerical simulation, including boreholes along seam, through seam in floor roadway, hygraulic flushing in hole to shield wind roadway, machine roadway and open-off cut tunneling in Ji_15-16-24100 working face, the influence of gas drainage on reducing the risk of outburst in working face was studied, and the drainage effect was verified by the field monitoring results. The results show that the comprehensive gas drainage of Ji_15-16 coal seam can effectively reduce the risk of outburst risk in the process of preparation and mining in Ji_15-16-24100 working face, the residual gas pressure value in Ji_15-16 coal seam is reduced to the range from 0.25 MPa to 0.45 MPa under this design scheme, the corresponding residual gas content of coal seam is reduced to the range from 2.8 m³/t to 4.5 m³/t, they meet the prevention requirements of coal and gas outburst in Pingmei No. 10 Coal Mine.