三软煤层巷道破坏机制及锚注对比试验

Failure mechanism of three soft coal seam roadway and comparison study on bolt and grouting

针对龙口矿区梁家煤矿典型软岩巷道—4606改造开切眼巷道围岩控制难题,通过现场监测和试验,分析原支护方案下围岩变形破坏机制。煤层结构复杂,围岩易膨胀、软化,围岩破坏范围大,拱架变形破坏严重,锚杆支护潜力无法有效发挥是巷道变形破坏的主要原因。支护构件锚固性能试验表明,与注浆前相比,注浆10 d后注浆锚杆拉拔力提高214%,高强锚索提高89%。在此基础上,以锚注支护为核心,实施了U型棚+注浆锚杆,注浆锚杆+高强锚索两种联合支护对比试验方案。结果表明:方案实施后,巷道围岩变形量小于原支护方案59%以上,锚注支护可有效控制该类条件下巷道围岩变形;两种试验方案的围岩整体平均变形量相差6.6%,采用注浆锚杆+高强锚索联合支护方案可替代传统的U型棚支护。

According to the field investigation and experiments at No. 4606 transform cut of working face in Liangjia coal mine,which is a typical soft rock roadway,the failure mechanism of surrounding rock under primary plan was analyzed.The results demonstrated that the complex structure of coal seam,the easy expansion and softening of surrounding rock,large destruction scope,serious arch deformation,and unrealized supporting potential were the main causes of rock failure.Anchorage performance tests show that compared with the drawing force before grouting,grouting bolts increase 214% after 10 days,and high strength cables increase 89%.Took bolt-grouting support as the core measure,two supporting test schemes,namely U type shed + grouting bolt and grouting bolt + high strength cable were proposed.The results show that the surrounding rock deformations are less than 59% compared with primary plan's,differed by 6.6%.Therefore,the grouting bolt + high strength cable can be used to replace U type shed.