近距离煤层群回采巷道失稳机制及其防治

 近距离煤层群开采过程中下层煤回采巷道将受到上煤层采空区遗留煤柱、本煤层邻近工作面动压的影响，针对崔家寨矿E12505工作面机巷出现的冒顶、底臌等严重现象，采用现场实测、理论分析及数值模拟等研究方法，探讨巷道失稳机制。研究结果表明，当上煤层采空区遗留煤柱宽度较小，下层煤巷道位于正下方、本煤层邻近工作面护巷煤柱较小时，受采动影响后巷道容易失稳；提出应距上煤层采空区遗留煤柱25 m、护巷煤柱尺寸20 m，加强巷道支护后可保证下层煤巷道稳定。据此，在E12611和E12504工作面进行工业性试验，取得较好效果。

INSTABILITY MECHANISM AND PREVENTION OF ROADWAY UNDER CLOSE-DISTANCE SEAM GROUP MINING

During the process of close-distance seam group mining，mining roadway in the lower seam is affected by coal pillar in the upper seam and the adjacent working face¢s mining. Due to the severe roadway roof caving and floor heave in the working face E12505 in Cuijiazhai coalmine，the field measurement，theoretical analysis and numerical simulation are adopted to study the mechanism of roadway¢s instability. The result shows that，when the upper pillar is narrow，the roadway is under the lower levels of the pillar and the protecting pillar is not wide enough，thus the roadway is easily damaged after the adjacent working face¢s mining. It is suggested that the distance between the roadway and the upper pillar is 25 m，and the protecting pillar is 20 m，so that the roadway can be stable in strengthened support. The industrial tests have been conducted at working faces E12611 and E12504，and good results have been achieved.