坚硬顶板条件下极软特厚高瓦斯煤层综放开采技术研究

Study on fully mechanized top-coal caving technology for ultra-soft extra-thick coal seam with high gas and hard roof

针对青东煤矿82采区828综放工作面复杂的开采技术条件,提出了预采7#煤层治理8#煤层瓦斯和控制8#煤坚硬顶板的开采方案。运用太沙基破坏理论分析了7#煤层底板破坏深度,利用岩梁理论分析了坚硬顶板的垮落步距,通过物理相似模拟实验分析了预采7#煤层和不事先预采情况下的覆岩运动规律,并对开采过程中的液压支架运行情况进行了现场实测。结果表明:726工作面底板破坏深度为13.8m,未破坏的剩余坚硬顶板厚度为5.3m,预采7#煤以后坚硬顶板断裂步距由24.9m减少到10.6m;相似模拟结果显示预采7#煤以后8#煤老顶垮落步距由20m减小到10m;实际生产过程中,液压支架运行状态良好,初次来压步距为20.4m,周期来压步距为10.4m。实践结果表明,预采7#煤层解决了828工作面开采过程中的坚硬顶板问题和瓦斯治理问题。

In view of the complex mining technical conditions of the 828 fully mechanized top - coal caving face in Qingdong Coal Mine, a mining plan was put forward to pre - mine upper No. 7 coal seam to control the hard roof and gas of No. 8 coal seam. Using the K. Terzaghi theory, the failure depth of coal seam floor was analyzed, and the hard roof caving interval was analyzed using Rock Beam Theory. Based on the physical material similarity simulation, the overlying strata movement rules with and without the pre - mining of No. 7 coal seam were analyzed. Working resistance of the hydraulic supports was analyzed through field test. The results showed that failure depth of 726 working face floor was 13. 8 m, and the thickness of undamaged hard roof was 5.3m. Fracture interval of the hard roof shortened from 24. 9m to 10. 6m after the pre - mining of No. 7 coal searrh The similar material simulation results showed that caving interval of hard roof in No. 8 coal seam shortened from 20m to 10m after the pre - mining of No. 7 coal seam. In the actual production process, the hydraulic supports worked effectively, the initial weighting interval was 20. 4m, and the periodic weighting interval was 10. 4m The results showed that pre - mining upper No. 7 coal seam solved the hard roof and gas problems in the mining of 828 working face.