煤层裂隙发育方向对瓦斯抽采效果影响的实验研究与应用

为了提高保德煤矿瓦斯抽采效率，实现高效抽采的目标，分析了保德煤矿8#煤层裂隙发育主方向及其与构造应力的关系，测试获得了沿主裂隙不同角度时煤样渗透率的变化规律。结果表明，8#煤层微观裂隙发育的主方向为与工作面呈23°左右的夹角。当煤样取样角度与裂隙发育方向平行时，煤体的渗透率最大|与裂隙发育方向垂直时，煤体的渗透率最小，随夹角的增大，煤体的渗透率逐渐减小。为验证实验结论，在现场施工了与裂隙发育方向分别呈30°、45°、60°、90°的四组抽采钻孔，结果表明当夹角为90°时，钻孔抽采瓦斯的浓度和纯流量最大，夹角为30°的时候最小。这表明井下施工抽采钻孔时，应充分考虑煤层微观裂隙的发育方向。

Experimental study and application of the influence of fracture development direction of coal seam on gas extraction effect

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.