由于急倾斜煤层地质条件与开采工艺的特殊性，在采用水平分层开采方式时下部卸压煤体释放的大量瓦斯流向回采工作面造成安全问题。为了治理急倾斜煤层综采工作面底部煤体瓦斯的威胁，降低急倾斜煤层底部煤体瓦斯流向回采工作面的浓度，提出了将水射流割缝与高压水力压裂相结合，形成切槽定向致裂增透急倾斜煤层底部区域煤体的瓦斯高效抽采技术。在神新集团乌东煤矿北区+500 m水平45号煤层东翼南巷40—400 m至上分层+525 m水平进行了工程试验研究。讨论与分析了急倾斜煤层切槽定向致裂瓦斯高效抽采技术的增透原理与工艺流程，制定了详细的现场工程试验方案，优选出了适用于急倾斜煤层切槽定向致裂瓦斯高效抽采技术的整套工艺技术装备。研究结果表明：采用切槽定向致裂瓦斯高效抽采技术增透急倾斜煤层回采工作面底部煤体瓦斯富集区域后，切槽定向致裂钻孔在注水压力为20 MPa条件下的瓦斯抽采纯量较普通瓦斯抽采钻孔提升了6.7倍，割缝钻孔瓦斯抽采纯量较普通瓦斯抽采钻孔提升了3.0倍；增透直接扰动半径约为6 m，70 d的抽采时间内影响半径已达到8 m以上。研究结果表明应用此技术治理急倾斜煤层回采工作面底部煤体瓦斯效果明显，有效保障了上分层回采工作面的安全生产。

Due to the special geological conditions and mining technology of the steeply inclined coal seam, when the horizontal slicing mining method is adopted, a large amount of gas will be released from the lower pressure relief coal body to flow to the working face, causing safety problems. In order to control the threat of gas in the bottom of the fully-mechanized mining face in steep coal seams and reduce the concentration of gas in the bottom of the steep coal seam flowing to the working face, it is proposed to combine water jet slotting with high pressure hydraulic fracturing to form a cutting slot with a directional orientation. A high-efficiency gas drainage technology in the bottom area of the sharply inclined coal seam by combining water jet slotting and high-pressure hydraulic fracturing to form grooves and directional fracturing to increase permeability is proposed. The engineering test was carried out in the south roadway of the east wing of the No. 45 coal seam at the +500 m level in the north area of Wudong Coal Mine of Shenxin Group, and the engineering test was carried out at the level of 40—400 m to the upper layer +525 m. Discussed and analyzed the principle and technological process of high-efficiency gas drainage technology for cutting slots in steeply inclined coal seams, formulated detailed on-site engineering test plans, and a complete set of technology and equipment suitable for high-efficiency gas drainage technology for cutting slots in steeply inclined coal seams has been selected. The results of the study show that: after adopting the cutting slot directional fracturing gas high-efficiency extraction technology to increase the penetration of the gas enriched area at the bottom of the steeply inclined coal seam, the cutting slot directional fracturing borehole can be used for gas drainage under the condition of 20 MPa water injection pressure. The scalar extraction rate is 6.7 times higher than that of ordinary gas drainage boreholes, and the scalar amount of gas extraction from slotted boreholes is 3.0 times higher than that of ordinary gas drainage boreholes; the direct perturbation radius of antireflection is about 6 m，and the radius of influence has reached more than 8 m in the 70 days drainage time. The radius of influence during the mining time has reached more than 8 m. The research results show that the application of this technology to control gas in the bottom coal body of a steeply inclined coal seam is effective, and it effectively guarantees the safe production of the upper slicing working face.