Department of Mining Engineering, Shanxi Engineering Vocational College
College of Safety and Emergency Management Engineering, Taiyuan University of Technology
Zuoquan Wulihou Coal Industry Co., Ltd., of Shanxi Lu’an Group

针对煤矿冲击地压引起的采掘安全问题，以山西晋中左权五里堠煤矿3号煤层开采地质条件为工程背景，提出一种基于钢锥冲击煤层的卸压方法。根据通电线圈间产生电磁互感斥力原理，获得磁力驱动绕线钢锥撞击煤层的冲击力函数式，并结合弹性力学理论，分析冲击力作用下煤体应力场分布特征、裂隙类型、破裂范围及程度。结果表明：(1) 冲击力与交流电电压及线圈级数呈正相关关系，与交流电频率及每米线圈匝数呈负相关关系。其中，电压是调控冲击力的最主要因素，综合考虑认为电压取660 V为宜。(2) 计算显示钢锥长度与直径仅需1 cm和1.28 cm，与之匹配的2级加速线圈总长为2 cm，可实现冲击装置的微型化，便于在钻孔内灵活布置。(3) 冲击力使钻孔横截面围岩出现集中系数为4.0~16.7的叶状极高应力区，其延伸长度为5倍钻孔半径，区内发育张拉裂隙；叶状区之外为集中系数1.7~3.3的高应力区，发育压剪裂隙，其范围可达50倍钻孔半径，据此得到卸压钻孔间距为2.5 m。(4) 按卸压段长度，每孔内设置2个间距2 m的冲击装置，冲击力使钻孔纵截面围岩呈现针状极高应力区，相邻针状区间分布椭圆形压剪裂隙区，两者一起贯通2 m厚煤层，实现有效破煤卸压。研究成果为探索基于磁力钢锥冲击的煤层卸压技术奠定初步理论基础。

This study aims to solve the mining safety problems caused by rock bursts in coal mines. With the geological mining conditions of the No.3 coal seam in the Wulihou coal mine in Zuoquan County, Jinzhong City, Shanxi Province as the engineering background, this study proposed a method for coal seam pressure relief based on steel cone impact. Specifically, based on the electromagnetic repulsion generated between energized coils, this study derived the functions of impact force produced when a magnetically driven coil-wound steel cone impacted the coal seam. Combining the theory on elastic mechanics, this study analyzed the stress field distribution, fracture types, and rupture ranges and degrees of the coal seam under the impact force. The results show that: (1) The impact force was positively correlated with AC voltage and the coil stage number but was negatively correlated with AC frequency and coil turns per meter. Voltage, the most significant factor in regulating the impact force, should be 660 V according to comprehensive consideration. (2) Calculations indicate that steel cones with a length and diameter of merely 1 cm and 1.28 cm each, respectively, along with matched two-stage accelerating coils with a total length of 2 cm, can achieve the miniaturization of the impact device for flexible arrangement in a borehole. (3) Under the action of the impact force, leaf-shaped zones subjected to extremely high stress occurred in the surrounding rocks along borehole cross sections. These zones exhibited stress concentration coefficients ranging from 4.0 to 16.7, an extension length 5 times the borehole radius, and extensional fissures. Outside these zones were high-stress zones, with stress concentration coefficients ranging from 1.7 to 3.3, an extension length up to 50 times the drilling radius, and the occurrence of compression-shear fissures. Therefore, the spacing between pressure relief boreholes should be 2.5 m. (4) Based on the lengths of pressure relief segments, two impact devices with a spacing of 2 m were installed in each borehole. Under the impact force, the surrounding rocks along the longitudinal sections of boreholes presented needle-shaped zones with extremely high stress. Elliptical zones with compression-shear fractures emerged among adjacent needle-shaped zones. Both types of zones jointly penetrated the 2-m-thick coal seam, achieving effective pressure relief on coal breaking. The results of this study lay a preliminary theoretical foundation for exploring technologies for coal seam pressure relief based on magnetically driven steel cone impact.

山西省高校科技创新基金项目(2019L1013)；山西省教育厅优质校建设专项科研项目(JY2019-YZ05)；山西工程职业学院重点科研项目(KYF-201907)

任智敏，吕梦蛟，王飞，等. 基于钢锥冲击的煤层卸压方法研究[J]. 煤田地质与勘探，2024，52(3)：37−47.

REN Zhimin，LYU Mengjiao，WANG Fei，et al. A method for coal seam pressure relief based on steel cone impact[J]. Coal Geology & Exploration，2024，52(3)：37−47.