中国矿山工程

In order to study the problems of floor pressure relief and gas control in the mining of close-distance coal seam group, by analyzing the development mechanism of floor rock pressure relief and plastic zone, the numerical simulation was used to analyze the effect of floor pressure relief and permeability enhancement after the mining of upper protective layer. and the effect of gas control in the mining of protective layer of close-distance coal seam group was verified through engineering practice. The results show that after the mining of the protective layer. the maximum failure depth of the floor rock layer can reach 17.8m, which is greater than the maximum vertical distance of 17 m between No.5 coal seam and No.9 coal seam, and No.9 coal seam is within the protection range. Through numerical simulation. the maximum depth of plastic zone of floor rock failure is 23m; after the working face of No.5 coal seam advances and exceeds the pressure measuring location, the gas pressure of the pressure measuring hole decreases by 46%~57.9%. indicating that the outburst risk of No.9 coal seam within the effective protection range of No.5 coal seam after mining has been eliminated. and the pressure relief effect is good.