Influence of Hydraulic Punching Coal Unloading Amount on Permeability Improvement

Based on the M9 coal seam of Guiqing Coal Mine, a gas flow solid coupling model was established under the condition of Klinken-berg effect. We simulate the influence of punching coal amount on permeability improvement, and draw a conclusion that effective influence radius of extraction is gradually increased with the increase of punching coal amount. However, when the expanding coal quantity of equivalent single hole increases to a certain degree, the range of effective extraction influence radius is decreased. It is appropriate to determine that the punching coal amount of M9 coal seam should be 1 t/m through analysis, the reasonable extraction time is 3 months, and the reasonable spacing of holes is 5 m×5 m. In engineering practice, the outburst elimination effect is good.