顺层长钻孔预抽瓦斯孔径确定及应用效果分析

Aperture determination and application effect analysis of bedding long boreholes along coal seam for gas pre-drainage

针对丁集矿煤层瓦斯高、地应力大及透气性差等特点,在巷道掘进工作面及煤壁两侧采取顺层长钻孔预抽瓦斯卸压消突措施。通过RFPA-Gasflow软件对钻孔周围煤的变形破坏特征、瓦斯流动特点及应力集中的变化进行数值模拟,获得合理瓦斯抽放钻孔参数,保证措施安全有效。结合模拟结果和现场钻孔施工实际确定抽放钻孔直径为133 mm,此时钻孔周围煤水平、竖直方向最大破坏范围达到520 mm和360 mm,掘进工作面前方煤卸压消突效果显著。

Aiming at the safe and high-efficient mining problems of the seam that are high in-suit stress,low permeability and high absorbability in Dingji coal mine,the bedding long boreholes along coal seam for gas pre-drainage is adopted to relief gas outburst elimination in the working face and both walls. The deformation and failure characteristics of coal,gas flow characteristics and the change of stress concentration were simulated through RFPA-Gasflow around borehole,then reasonable gas drainage drilling parameters were acquired,and safe and effective measures were ensured. Holes diameter was determined as 133 mm combining with simulation results and on-site drilling conditions,and the horizontal and vertical maximum range of destruction around single borehole were 520 mm and 360 mm. The effect of pressure relief and outburst of coal body is remarkable in front face of driving working face.