Research on the law of pressure relief and permeability increase in overlying coal seam of floor roadway

Abstract

To study the law of pressure relief and permeability enhancement in the overlying coal seams of different rock pillar floor roadways, the air permeability coefficients at different positions of the overlying coal seams of 710-floor roadways and 505-floor roadways were measured on site. Through investigation, it is found that the air permeability coefficient of the coal seam directly above the pressure relief floor rock roadway is the largest, followed by the upper and lower banks at 7.5 m, and the upper and lower banks at 15 m. Comprehensive analysis shows that with the increase in excavation time, the permeability of the coal seam corresponding to the drill hole gradually increases, and the pressure relief effect gradually increases. The smaller the distance between the floor roadway and the coal seam, the more significant the anti-reflection effect.