密集钻孔卸压技术在下分层沿空留巷中的应用研究

Research on the Application of Dense Drilling Pressure Relief Technology in Lower Layered Gob Retaining Roadway

针对高应力底分层沿空留巷期间顶板压力大且留巷围岩变形严重的问题,以古汉山矿15032底分层工作面为研究背景,综合采用现场实测、理论分析和数值模拟相结合的方法,提出密集钻孔卸压技术,研究分析了底分层工作面覆岩结构特征及切顶关键参数,并进行现场实践应用。结果表明:底分层工作面假顶之上所存在的完整且较大的块体结构是造成留巷压力大的关键因素;确定了合理的切顶高度18 m、角度80°,钻孔间距200 mm,钻孔直径50 mm;现场实施后留巷段顶板下沉356 mm、两帮收缩量656 mm,围岩变形在可控范围之内,经简单卧底修复后能满足接替工作面正常回采的要求。

In response to the problem of high roof pressure and severe deformation of the surrounding rock during the goaf retaining period of high stress bottom layering,taking the 15032 bottom layering working face of Guhanshan Mine as the research background,a dense drilling pressure relief technology was proposed by combining on-site measurement,theoretical analysis,and numerical simulation.The characteristics of the overlying rock structure and key cutting parameters of the bottom layering working face were studied and analyzed,and on-site practical application was carried out.The results indicate that the complete and large block structure above the false roof of the bottom layered working face is the key factor causing the high pressure of the retained roadway;A reasonable cutting height of 18m,angle of 80°,drilling spacing of 200mm,and drilling diameter of 50mm have been determined;After on-site implementation,the roof of the remaining roadway section sank by 356mm and the shrinkage of the two sides was 656mm.The deformation of the surrounding rock was within a controllable range,and after simple underground repair,it could meet the requirements for normal mining of the replacement working face.At the same time,it provides technical reference for the practical application of goaf retaining under similar conditions.