厚硬顶板大面积悬顶是诱发冲击地压的重要原因之一，针对顶板深孔爆破和常规水力压裂存在的不足，开发了磨砂射流轴向切顶技术。该技术通过在巷道顶板钻孔内实施预制轴向裂缝、定向水力压裂等工序，使巷道走向和倾向方向上均形成最有利于顶板垮落的人造裂缝网，以实现最佳卸压效果。现场应用表明，实施磨砂射流轴向切顶后，目标岩层电磁波吸收系数增强，顶板裂隙明显增加；工作面回采期间，压裂影响区域的支架支撑力在增加，支架主要受力模式从降阻型和恒阻型转变为增阻型，微震能量释放更平稳，有效降低了冲击地压发生风险。在此基础上，分析了磨砂射流轴向切顶卸压防冲机理，即轴向切顶使工作面端头附近形成预制的轴向裂缝，工作面回采期间，顶板沿预制裂缝定向切落，降低了顶板弯曲弹性能转化为巷道围岩压缩弹性能的基础静载E_j和顶板突然断裂产生的强烈附加动载E_d，使巷道围岩不具备冲击启动的载荷条件。

The large area overhanging of thick and hard roof is one of the critical reasons for inducing coal burst. Because of the shortcomings of deep borehole blasting and conventional hydraulic fracturing for the overhanging roof, the axial roof cutting technology of abrasive jet was developed. This technology achieves the best pressure relief by implementing prefabricated axial fractures and directional hydraulic fracturing in the roadway roof borehole to create an artificial fracture network in the roadway direction and tendency direction that is most conducive to roof collapse. The field application shows that the electromagnetic wave absorption ability of the stratum was enhanced, and the apparent resistivity was increased after the axial cutting roof technology of abrasive jet was implemented. During the mining operation of working face, the stress condition of the support was improved, and the release of micro-seismic energy was more stable, effectively reducing the risk of coal burst. On the basis of site observation, the mechanism of coal burst prevention by axial roof cutting of abrasive jet was revealed, that is, the plate-like structure fixed on both sides near the working face end is damaged by axial roof cutting, reducing the basic static load E_j, which is converted from the bending elastic energy of roof into the compression elastic energy of roadway surrounding rock, and reducing the strong additional dynamic load E_d, which is generated by the sudden fracture of roof, so that the roadway surrounding rock does not have the loading conditions for starting coal burst.