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对大断面破碎围岩多次返修巷硐,锚网索支护方式难以有效控制其强流变。结合焦煤公司中马村矿39#泵房多次返修的状况,认为高应力作用下的不稳定强流变岩层,支架受力不均等因素是硐室围岩失稳的主因,提出了主动支护与被动支护联合修复方案:一次锚网索支护,二次封闭刚性支架联合支护,三次围岩注浆加固。采用蠕变数值模拟方法对原支护和返修加固方案进行了分析,结果表明:原方案在360 d时的断面收缩率达到92.2%,顶板最大下沉量达到2 792 mm,围岩处在加速蠕变失稳阶段;返修加固方案在1 000 d时的顶板最大下沉量仅56.8 mm,围岩处在蠕变稳定阶段;锚索作用在完整岩体范围内,锚杆大部分作用在塑性圈范围内,注浆范围外应力等值线密集,其峰值随时间的延长而增大,且逐渐内移。工业性试验表明:224 d时,硐室表面最大位移为18 mm,变形速率小于0.5 mm/d,修复加固取得了成功。
It is difficult to effectively control the strong rheological deformation of the tunnel with the large section of crushed rock repeatedly repaired. Combined with the repeated rework of 39 # pumping station in Zhongmacun Mine of coking coal company, it is considered that the unstable rock with strong rheological stress under high stress is the main cause of the instability of surrounding rock of the chamber, and the active branch Protection and passive support joint repair program: an anchor net support, secondary closed rigid support joint support, grouting three times the reinforcement. The creep numerical simulation method is used to analyze the original supporting and reworking reinforcement schemes. The results show that: the original scheme has a reduction of area of 92.2% at 360 days and a maximum roof subsidence of 2 792 mm, and the surrounding rock is accelerating The maximum subsidence of the roof at 1 000 d is only 56.8 mm, the surrounding rock is in the stage of creep stability; the anchor cable acts in the range of intact rock mass, and the anchor mostly acts on the plasticity Within the circle range, the stress contour outside the grouting range is intensive, and its peak value increases with time and gradually moves inwards. The industrial tests show that the maximum displacement of the chamber surface is 18 mm and the deformation rate is less than 0.5 mm / d at 224 days. The restoration and reinforcement have been successful.