“三软”巷道长短锚索联合支护控制变形研究

Research on deformation control of long and short anchor cable combined support in“three soft”roadway

针对“三软”特厚煤层巷道围岩变形严重、控制难度大、掘进效率低、采掘接替困难的难题,提出了一种锚网索支护控制技术。采用现场超声波探测及钻孔窥视揭露方法,测定围岩松动圈塑性范围为2.4~3.0 m;采用数值模拟得到锚索不同间距下的支护效果,确定顶板采用锚网索、两帮采用锚杆的支护方案,设计合理的支护间距,并成功进行了工程应用。结果表明,长、短锚索联合支护可有效控制复合软岩巷道的变形。两帮和顶底板的移近量不大于30 mm;掘进期间顶锚索应力为60~170 kN,受力较为稳定。可见长短锚索联合控制技术可有效提高巷道围岩控制效果,而且生产实践表明,采用长短锚索联合控制技术后平均月进度突破143 m(架棚支护平均月进度60 m),掘进效率实现成倍增长,有效解决了采掘接替困难问题,经济社会效益显著。

In response to the challenges of severe deformation,difficult control,low excavation efficiency,and challenging mining replacement in the surrounding rock of“three soft”ultra-thick coal seam roadways,a control technology utilizing anchor net cable support is proposed.Through on-site ultrasonic detection and borehole observation,the plastic range of the loose zone in the surrounding rock is determined to be from 2.4 m to 3.0 m.By using numerical simulation,the supporting effect under different spacing of long and short anchor cable is obtained.The supporting scheme of using anchor net cable for roof and using rock bolt for two ribs is determined.The reasonable supporting distance is designed and successfully applied in practice.The results show that the combined support can effectively control the deformation of composite soft rock roadway.The convergence of the two ribs and the roof and floor is not more than 30 mm;during roadway excavation,the stress of roof anchor cable is in the range of 60 kN to 170 kN,which is relatively stable.It can be seen that the combined control techniques of long and short anchor cables can effectively improve the control effect of roadway surrounding rock.Moreover,the production practice has proved that the average monthly footage of the long and short anchor cable combined control technology has exceeded 143 m(compared to an average monthly advancement of 60 m with shed support),the excavating efficiency has increased exponentially,and the difficulty of mining replacement has been effectively solved.The economic and social benefits are significant.