Abstract Roadway failure control in modern longwall mining has been universally difficult and needs to be resolved. To address the failure of retained roadways in longwall mining, in this study, a novel approach of directional roof presplitting (DRP) is introduced and examined through a field experiment. The DRP method utilizes the mine pressure effect and broken expansion nature of rock to achieve the active pressure relief of retained roadways. Directional tensile blasting presplits the trial roadway roof by forming a smooth fracture surface in the roof. After mining, the gob roof within the presplitting height caves in under the mine pressure and subsequently expands to fill the gob to counter the mine pressure. A field test was conducted, and a comprehensive monitoring scheme and a system were designed to study the DRP effect. The results indicated that, the trial roadway roof can be directionally cut apart under the guidance of the charge test and with the help of the established theoretical model for hole distance; after blasting, the roof could maintain its reliability, even though the working face approached. After mining, the retained roadway with DRP exhibited good pressure relief. Roof integrity was guaranteed; furthermore, roadway convergence significantly decreased, and sidewall stability on the pillar side was improved because the high pressure transferred to a farther position. In addition, DRP reduced the scope and degree of the lead abutment pressure and the periodic weighting loads on the working face. This study provides an effective and practical way to control retained roadways and potentially discusses a new approach for utilizing the geomechanical characteristics to prevent and control the mine pressure disasters.

中文翻译：

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定向顶板预裂对留存巷道泄压现场试验

摘要 现代长壁开采巷道破坏控制一直是一个普遍的难题，亟待解决。为了解决长壁开采中保留巷道的故障，在本研究中，通过现场试验引入并检验了定向顶板预裂 (DRP) 的新方法。DRP法利用矿井压力效应和岩石破碎膨胀特性，实现保留巷道主动泄压。定向拉伸爆破通过在顶板中形成光滑的断裂面来预裂试验巷道顶板。开采后，预裂高度内的采空区顶板在矿压下塌陷，随后膨胀填充采空区以抵消矿压。进行了现场测试，并设计了综合监测方案和系统来研究 DRP 效果。结果表明，在荷电试验指导下，借助建立的孔距理论模型，可以对试验巷道顶板进行定向切割；爆破后，即使接近工作面，屋顶仍能保持其可靠性。开采后，保留有 DRP 的巷道表现出良好的减压效果。屋顶完整性得到保证；此外，由于高压转移到更远的位置，道路收敛显着减少，柱侧的侧壁稳定性得到改善。此外，DRP 减小了工作面铅台压力和周期性加重载荷的范围和程度。