为验证顶板高位大直径定向钻孔在三元煤矿的适应性、成孔孔径大小对瓦斯抽采效果的影响,在试验工作面试验施工了两组不同孔径的顶板高位大直径定向钻孔。针对三元煤矿地质条件复杂、断层构造多、不稳定地层较多的问题,在试验过程中采用复合钻进工艺和碎软煤层定点注浆加固工艺,以保障顶板高位大直径定向钻孔钻进至设计孔深。试验结果显示,采用复合钻进工艺和碎软地层定点注浆加固工艺能有效提高钻孔的成孔性以及成孔深度,且对两组不同孔径的顶板高位大直径定向钻孔瓦斯抽采数据进行对比分析,Ф203mm孔径钻孔瓦斯抽采混合量和抽采纯量为Ф153mm孔径钻孔的2.06倍及1.82倍,瓦斯抽采能力大大加强。

To verify the adaptability of roof high position large-diameter directional borehole in Sanyuan Coal Mine and the influence of pore-forming pore size on gas extraction effect, two sets of roof high position large-diameter directional borehole with different pore sizes are tested and constructed on the experimental working face. In view of the problem of complex geological conditions, multiple fault structures, and many unstable strata in Sanyuan Coal Mine, composite drilling technique and broken and soft coal seam fixed-point grouting reinforcement technique are adopted in the experimental process to ensure that the roof high position large-diameter directional borehole is carried out to the designed hole depth. The experimental results show that the use of composite drilling technique and broken and soft strata fixed-point grouting reinforcement technique can effectively improve the borehole pore-forming property and pore-forming depth. In addition, a comparative analysis is conducted on the gas extraction data of two sets of roof high position large-diameter directional borehole with different pore sizes. The gas extraction mixing amount and extraction pure quantity of the borehole with a pore size of Ф 203 mm are 2.06 times and 1.82 times than that of the borehole with a pore size of Ф 153 mm, respectively, greatly enhancing the gas extraction capacity.