急倾斜三软厚煤层留小煤柱沿空护巷技术

在急倾斜三软厚煤层走向长壁俯伪斜采煤条件下实施留小煤柱沿空护巷十分困难,煤柱稳定性和巷道围岩变形极难控制。针对这一难题,提出了包含煤柱小角度锚固法和十字护顶方法的留小煤柱沿空护巷技术,有效解决了煤柱易沿顶底板剪切破坏并向巷内搓动的问题,降低了巷道软弱围岩的破碎程度和变形量。现场试验结果显示,留设小煤柱的完整性保持较好,其中相较于原支护方式顶底板移近量减少了40%,两帮收敛量则减少了42%,巷道围岩变形得到了有效控制。与此同时,还得到工作面前后方回采巷道的矿压显现呈现明显的6个分区,分别为工作面前方无影响区、工作面前方矿压显现影响区、工作面前方矿压显现强烈区、工作面后方顶板激烈活动区、工作面后方顶板活动减缓区和工作面后方基本稳定区。其中,工作面前方矿压显现强烈区和工作面后方顶板活动激烈区的范围明显大于缓斜近水平煤层,这为分区制定围岩控制措施提供了有利依据。所得研究成果可为我国急倾斜走向长壁俯伪斜工作面沿空护巷技术研究提供一定的补充。

Gob Side Entry Protection Technology of Small Coal Pillar in Steeply Inclined Three-Soft Thick Coal Seam

It is quite difficult to protect the roadway along the gob with small coal pillars under the condition of long-wall and false-inclined mining in steeply inclined three-soft thick coal seams. The stability of coal pillars and the deformation of the surrounding rock of the roadway are extremely difficult to control. In response to this problem, the technology of retaining small coal pillars along the goaf including the coal pillar small angle anchoring method and the cross roof protection method is proposed, which effectively solves the problem that the coal pillars are easy to shear along the roof and floor and move into the roadway, and reduces the degree of fracture and deformation of the weak surrounding rock of the roadway. The field test results show that the integrity of the small coal pillar is maintained well. Compared with the original support method, the roof and floor movement is reduced by 40%, the convergence of the two sides is reduced by 42%, and the surrounding rock deformation of the roadway is effectively controlled. At the same time, the mine pressure behavior of the roadway in front and behind the working face is divided into six obvious zones, which are no influence zone in front of the working face, influence zone in front of the working face, strong mine pressure behavior zone in front of the working face, intense roof activity zone behind the working face, slow roof activity zone behind the working face and basic stability zone behind the working face. The range of the area with strong ground pressure behavior in front of the working face and the area with severe roof activity in the rear of the working face is obviously larger than that of the gently inclined near horizontal coal seam, which provides a favorable basis for formulating surrounding rock control measures in different zones. The research results can provide a certain supplement for the study of gob side entry protection technology in steeply inclined longwall inclined and pseudo inclined working face in China.