深部破碎巷道锚网注耦合支护技术试验研究

Experimental Study on Anchor-net-grouting Coupled Support Technology in Deep Broken Roadway

针对金川矿区深部破碎围岩巷道在高应力作用下支护结构变形较为严重的情况,提出了预应力中空注浆锚杆+柔性TECCO网+注浆的耦合支护技术。通过DDA方法对巷道开挖后的围岩破坏规律进行了研究,数值模拟结果表明,巷道开挖后其顶、底板的围岩破坏深度要大于巷道两帮,为现场支护方案设计提供了参考依据。现场支护试验表明,采用该项支护技术可以有效提高支护结构的强度与刚度,给深部破碎围岩提供了"先柔后刚"两阶段的耦合支护,对围岩的变形控制起到了"先让后止"的平衡作用。巷道支护20d后,围岩变形速率小于0.05mm/d,巷道顶板的平均下沉量为32mm,两帮相对位移量平均值为44mm,表明该支护方法能有效控制巷道变形。试验巷道支护3a后无需任何返修,返修周期提高3倍以上,大大降低了巷道支护与维护的综合成本。

Aiming at the serious deformation of the reinforcing structure in broken surrounding rock roadway in the deep mining of Jinchuan mining area under high stress,the coupled support technology of prestressed hollow anchor-net-grouting was proposed.The damage law of surrounding rock after roadway excavation was studied by DDA method.The numerical simulation results showed that the surrounding rock damage depth at the top and bottom of the roadway after excavation was larger than that at two sides of the roadway,which provided a reference for the design of the site support scheme.The on-site support test showed that this coupled support technology not only improved the strength and rigidity of the support structure,but also provided a two-stage coupled support of "first softening then rigid" for the deep broken surrounding rock,as well as played a balance of "first letting back then stoping" for the deformation control of the surrounding rock.After 20 days of roadway support,the deformation rate of surrounding rock was less than 0.05 mm/d,the average subsidence at the roof of the roadway was 32 mm,and the average relative displacement of the two sides was 44 mm.The results indicated that the support method can effectively control the deformation of the roadway.After 3 years of test roadway support,the roadway was intact and did not require any repairs.The repair cycle was improved by more than 3 times,which greatly reduced the comprehensive cost of roadway support and maintenance.