坚硬顶板下近距离煤层群切顶卸压技术研究

Roof cutting technology for pressure relief and hanging roof caving in contiguous coal seams under hard roof

针对存在多层坚硬顶板的近距离煤层巷道在工作面开采时处于高应力状态难以维护的问题,以西铭矿近距离煤层为研究对象,采用理论分析和数值模拟相结合,提出了坚硬顶板条件下近距离煤层开采通过切顶卸压消除顶板悬顶结构的方法,研究切顶位置和煤柱宽度对巷道围岩应力及稳定性的影响。研究表明,含多层坚硬顶板的近距离煤层开采时,在上位煤层开采完毕后,存在不利下位煤层巷道围岩稳定的大跨度悬顶结构;合理的切顶位置能有效消除悬顶效应对下位煤层巷道围岩应力分布的影响;上位煤层煤柱宽度影响下位煤层巷道围岩变形率,30m煤柱宽度是巷道围岩变形速率的临界分界点。

It’s difficult to maintain the high-stress roadway during coal face mining in contiguous coal seams with multi-layer hard roofs.Taking the contiguous coal seams of Ximing Mine as the research object,theoretical analysis and numerical simulation are carried out.It's proposed to use roof cutting for the pressure relief and hanging roof caving in contiguous coal seams under hard roof.The influence of roof cutting position and coal pillar width on the stress and stability of the surrounding rock of the roadway is studied.The research shows that,after the upper coal seam is mined,a long-span hanging roof structure forms,which is unfavorable to the surrounding rock stability of the lower coal seam roadway;a reasonable roof cutting position can effectively eliminate the hanging roof effect on stress distribution on surrounding rock of the lower coal seam roadway;the upper coal pillar width affects the surrounding rock deformation rate of the lower coal seam roadway,and 30m is the critical width of coal pillar in terms of the surrounding rock deformation rate.