1 College of Safety Science and Engineering, Xi'an University of Science and Technology
Western Coal Mine Gas Disaster Prevention and Control Key Laboratory of Colleges and Universities in Shaanxi Province
Western Engineering Research Center of Mine Gas Intelligent Drainage for Coal Industry

沿空留巷开采是我国煤炭可持续发展的重要方向之一,其采动覆岩卸压瓦斯运移储集区演化与传统开采方式有所不同。为进一步准确辨识沿空留巷开采覆岩卸压瓦斯运移储集区,通过数值模拟及物理相似材料模拟,研究了切顶侧与未切顶侧的裂隙特征,分析了采动覆岩裂隙动态发育过程及应变分布规律,提出了沿空留巷开采卸压瓦斯抽采靶区位置判别方法,并进行了现场工程实践。研究结果表明:低位覆岩受切顶影响,易发生破断垮落;高位覆岩区域未切顶侧覆岩裂隙较为发育,切顶侧与非切顶侧裂隙发育高度相同。采动裂隙形态、覆岩应变形态均呈梯形,随覆岩周期破断,采动裂隙呈跃进态势向上发展。不同区域采动离层裂隙角度集中在0°~10°,竖向破断裂隙区角度主要集中在80°~120°。基于关键层判别、采动裂隙角度及数量、覆岩应变特征等,结合通风方式,提出沿空留巷开采卸压瓦斯抽采靶区判定方法,将抽采钻孔布置在“采动裂隙锐角发育区+高瓦斯体积分数”区域,判定得出试验工作面抽采靶区为与煤层顶板垂距30~46m、与辅运巷平距30~55m的区域。试验工作面开采期间整体瓦斯抽采效果良好,说明基于沿空留巷开采卸压瓦斯抽采靶区判定方法设计的抽采钻孔具有合理性,可为沿空留巷开采“Y”型通风方式下卸压瓦斯抽采钻孔设计提供一定参考。

Gob-side entry retaining mining is one of the important directions of sustainable development of coal in China. The evolution of pressure relief gas migration reservoir area in mining overburden is different from that of traditional mining methods. In order to further accurately identify the pressure-relieved gas migration reservoir area of overburden strata in gob-side entry retaining mining, the characteristics of fractures on the roof-cuttingside and the non-roof-cutting side were studied by numerical simulation and physical similarity simulation. The dynamic development process and strain distribution law of mining-induced overburden fractures were analyzed. The method of identifying the location of pressure-relieved gas extraction target area in gob-side entry retaining mining was proposed, and the field engineering practice was carried out. The research shows that the low-position overburden rock is affected by roof cutting and is prone to fracture and collapse, while the overburden rock cracks on the uncut side of the high-position overburden rock area are relatively developed, and the development height of the cracks on the cutting side and the non-cutting side is the same. The shape of mining-induced fractures and the strain shape of overburden rock are trapezoidal. With the periodic fracture of rock strata, the mining-induced fractures develop upward in a leap-forward trend. The angle of mining-induced bed separation fracture in different regions is concentrated in 0°–10°, and the angle of vertical fracture zone is mainly concentrated in 80°–120°. Based on the identification of key strata, the angle and number of mining-induced fractures, and the strain charac-teristics of overlying strata, combined with the ventilation mode, a method for determining the target area of pres-sure-relieved gas extraction in gob-side entry retaining mining is proposed. The extraction boreholes are arranged in the area of ''acute angle development area of mining-induced fractures + high gas volume fraction''. It is deter-mined that the extraction target area of the test working face is 30–46 m from the vertical distance of the coal seam roof and 30–55 m from the horizontal distance of the auxiliary transportation roadway. The overall gas ex-traction effect during the mining period of the test working face is good, indicating that the extraction borehole designed based on the determination method of the pressure-relieved gas extraction target area of the gob-side entry retaining mining is reasonable. The research results can provide some reference for the design of pressure-relieved gas extraction boreholes under the ''Y'' type ventilation mode of gob-side entry retaining mining.

国家自然科学基金面上资助项目(52074217);国家自然科学基金青年资助项目(52204240)

1 试验方案
1.1 工程背景概况
1.2 物理相似模拟试验方案
1.3 数值模拟试验方案
2 沿空留巷开采覆岩裂隙演化规律
2.1 沿工作面走向覆岩裂隙演化特征
2.2 沿工作面倾向覆岩裂隙演化特征
2.3 沿工作面走向覆岩应变规律
2.4 不同区域裂隙参数特征
3 沿空留巷开采卸压瓦斯抽采技术
3.1 卸压瓦斯抽采靶区确定
3.2 卸压瓦斯抽采钻孔布置
3.3 抽采效果分析
4 结论

林海飞, 刘思博, 双海清, 等. 沿空留巷开采覆岩裂隙演化规律及卸压瓦斯抽采技术[J]. 采矿与岩层控制工程学报, 2024, 6(1): 013537.

LIN Haifei, LIU Sibo, SHUANG Haiqing, et al. Overburden rock fracture evolution law and pressure relief gas extraction technology of gob-side entry retaining mining[J]. Journal of Mining and Strata Control Engineering, 2024, 6(1): 013537.