白皎矿保护层沿空切顶成巷无煤柱开采技术研究

Research on the Technique of No-Pillar Mining with Gob-Side Entry Formed by Advanced Roof Caving in the Protective Seam in Baijiao Coal Mine

为解决白皎煤矿保护层留煤柱引发的采空区瓦斯积聚、瓦斯突出及应力集中对近距离煤层开采引起的灾害问题,提出了深井工作面卸压沿空切顶成巷无煤柱开采方法,对沿空巷道顶板实施超前预裂,切断沿空巷道顶板与采场直接顶、基本顶的联系,在周期来压作用下采场顶板沿预裂面切落形成巷帮,隔断采空区并支撑上位移动岩层,改善了巷道围岩应力环境,将巷道围岩应力集中转移到深部,实现巷道稳定.该方法采用超前双向聚能张拉爆破沿走向预裂顶板,能减小对顶板的爆破损伤;采用巷内恒阻大变形锚杆(索)+巷旁锚索加强支护+巷旁密集单体液压支柱加强切顶联合支护技术,适应巷内围岩大变形及切顶冲击变形的要求,以控制巷道围岩稳定;开发了远程矿压监测系统,实时监控留巷过程顶板稳定性.基于该方法的配套关键技术在白皎矿2422保护层开采工作面机巷得到成功应用,为深部煤矿长壁工作面提供一种经济有效的无煤柱开采新理论与技术.

To solve the disasters during the mining of close distance seams, which are affected by gas accumulation in goal, gas outburst and stress concentration caused by coal pillars sup- port mining in the protective seam in Baijiao coal mine, we proposed the method of no-pillar mining with gob-side entry formed by forced roof caving in the deep-level faces. After cutting off the connection between the roof above gob-side entry and the immediate and main roofs, by advanced pre-split blasting in the roof above gob-side entry, the stope roof will cut off along the pre-split surface, and the side of entry will formed under the action of periodic weightings, which can separate the goaf and support the overlying moving strata, improve the surrounding rock stress environment, transfer the concentrated stress into the deep part, and ensure the entry stability. In this method, the advanced bilateral cumulative tensile explosion is used for roof pre-splitting along the strike and to reduce the blasting damage to the roof as well. The joint supporting technique composed of road-in constant resistance and large deformation bolts/ cables, roadside reinforced cables, and roadside dense hydraulic props, to adapt the large de- formation of surrounding rock and impact deformation in roof cutting, and control the roadway stability. Moreover, the remote ground pressure monitoring system is developed to monitor the roof stability continuously in the roadway retained process. The corresponding key technique has been applied successfully in the tailentry of protective face 2422 in Baijiao coal mine, which provides a new economic and effective theory and technique for no-pillar mining in deep-level longwall faces.