分析了旋转射流破煤增透机理,据此研发了井下高压旋转水射流扩孔系统装备及工艺并在城山煤矿进行了现场试验。现场应用表明:高压水射流扩孔后的钻孔孔径为扩孔前孔径的3.3倍;100 m钻孔的平均瓦斯抽放速度是常规钻孔的1.79倍。旋转射流扩孔增加了钻孔周边煤体的卸压范围,提高了煤体的渗透系数,从而大幅度提高了瓦斯抽放量。 Based on the analysis of the penetrating mechanism of rotary jet coal breaking, the equipment and technology of the downhole high pressure rotary water jet reaming system were researched and field tests were carried out in Chengshan Coal Mine. The field application shows that the bore diameter after reaming of high pressure water jet is 3.3 times of the bore before reaming, and the average gas drainage speed of 100 m bore is 1.79 times of conventional drilling. The revolving jet reaming increases the pressure relief range of the coal surrounding the borehole and increases the permeability coefficient of the coal so as to greatly improve the gas drainage amount.