膨胀软岩顶板回采巷道支护技术研究

Research on roof falling mechanism and support technology of mining roadway in expansive soft rock

膨胀型软岩巷道易变形破坏乃至冒顶,其关键问题是机理认识不清以及支护方案不当。以李家楼煤矿1202轨道巷为背景,采用室内试验、现场实测、理论分析与数值模拟等方法研究了膨胀软岩巷道的冒顶机理及其支护优化方法。研究结果表明:(1)1202轨道巷顶板2~4 m有泥岩,泥岩中黏土矿物含量高达70%,其中蒙脱石含量高达25%,因此泥岩极易遇水崩解;(2)膨胀软岩巷道冒顶原因为:直接顶有软弱夹层+强降雨与空气潮湿+支护方式不合理,且支护参数较弱;(3)膨胀软岩巷道的新型支护方式为:锚杆+金属网+钢筋梯子梁+锚索补强联合支护,应提高其预紧力与锚固力,防止直接顶离层以及基本顶悬吊作用的拉力不够。现场监测发现,随着工作面的推进,巷道顶板总离层量最大为12 mm,围岩稳定性较好。

It is easy to destroy in expansive soft rock roadway with the large deformation and roof falling.The key problems are the mechanism is not clear and the support scheme is not reasonable.Based on the 1202 track roadway in Lijialou Coal Mine,by conducting laboratory experiments,field measurements,theoretical analysis and numerical simulation,the mechanism of roof falling and reasonable support scheme were studied.The results showed:(1)there are mudstones in the 2 to 4 m roof of the 1202 track,the clay mineral content in the mudstone is as high as 70%,and the montmorillonite content is as high as 25%,therefore,the mudstone is easily disintegrated by water;(2)the reason of roof falling were the presence of weak interlayer in immediate roof,strong rainfall,moist air,unreasonable support scheme and low support parameters;(3)the new support method for expansive soft rock roadway was combined with support including bolt,metal mesh,steel ladder beam and reinforced anchor cable.Also its pre-tightening force and anchoring force should be improved to prevent immediate roof separation and the lack of pulling force of the top suspension.The on-site monitoring system showed that the total separation of the roof of the roadway was 12 mm with the advancement of working face.The surrounding rock is at good conditions.