关键词: 微观裂隙, 瓦斯抽采, 煤层走向, 渗透率

Abstract: Based on the analysis of the characteristics of fracture development and tectonic stress evolution in Baode coal mine, the fracture development direction of coal seam in the three panel of Baode coal mine is obtained. After retrieving the large coal briquettes on site and drilling the coal sample at different angles with the direction of fracture, the permeability variation rule under different conditions was tested and analyzed. The results show that when the sampling angle is parallel to the direction of fracture development, the permeability of coal is the largest. When the sampling angle is perpendicular to the direction of fracture development, the permeability of coal is the minimum. With the increase of the angle, the permeability of coal decreases gradually. This phenomenon indicates that the drilling hole should be perpendicular to the direction of fracture development, so that gas flows directly into the drilling hole along the fracture. Four groups of test drainage boreholes were arranged on the 81310 working face of Baode coal mine, making the included angles of boreholes and fracture direction are 30, 45, 60 and 90° respectively. The effect of extraction shows that the drainage effect of drainage boreholes in different directions is different. When the included Angle is 90°, the actual drainage effect of gas drainage boreholes is the best, and the drilling arrangement is the optimal plan.