针对煤层群开采时上覆集中煤柱下矿压显现强烈的问题,以上湾煤矿22104大采高工作面煤柱下开采为工程背景,分析了集中煤柱下开采存在的矿压显现危险性。采用数值模拟研究了来压时和来压后集中煤柱下开采循环的顶板应力变化规律,得出来压前后顶板压力存在的巨大差异会导致工作面进出煤柱时可能产生强矿压显现。针对在上层煤停采线前可能存在危险区,制定了详细的水力压裂解危方案并成功实施,结果表明水力压裂技术能够显著降低顶板强度和煤柱内应力集中程度,减小顶板来压步距,实现了大采高工作面过集中煤柱的安全开采。

In view of the strong ground pressure under the overlying concentrated coal pillar in coal seam group mining, taking the mining under the coal pillar in 22104 working face with large mining height in Shangwan Coal Mine as the engineering background, the problem of ground pressure under the concentrated coal pillar mining in goaf were analyzed. Numerical simulation was used to study the variation of roof stress in the mining cycle under concentrated coal pillar during and after weighting. It was found that the huge difference of roof pressure before and after weighting would lead to strong ground pressure when the working face entered and exited the coal pillar. In view of the danger zone that may exist before the upper coal stopping line, a detailed hydraulic fracturing danger scheme is formulated and successfully implemented. The results show that hydraulic fracturing technology can significantly reduce the roof strength and the concentration of internal stress in coal pillar, reduce the weighting interval of roof, and realize the safe mining of over-concentrated coal pillar in large mining height working face.