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深井近距离煤层群回采巷道失稳致因与控制技术

Stability lost causes and control technology of mining gateway in deep mine with contiguous seams

  • 摘要: 为解决深井近距离煤层群动压开采条件下回采巷道围岩控制难度大的问题,采用理论分析与现场勘探相结合的方法,分析了深井近距离煤层群动压开采条件下回采巷道变形失稳致因。分析可知矿井复杂高应力环境、巷道围岩性质弱化和支护方式及参数不合理是导致回采巷道变形失稳的关键原因,在此基础上综合运用"围岩应力释放、围岩补强支护、围岩改性增强、围岩应力转移"的围岩控制原理,并结合实际提出"锚网喷让压支护+预应力锚索补强支护+锚注改性支护+大孔径钻孔卸压"相结合的围岩控制对策。现场应用结果表明:巷道表面变形量不超过200 mm,只有巷道局部开裂、个别锚杆锚索破坏现象,没有出现底鼓和片帮;巷道掘进期间,两帮最大移近量为75 mm,顶底板最大移近量为56 mm,工作面回采期间,两帮最大移近量为101 mm,顶底板最大移近量为77 mm。

     

    Abstract: In order to solve high difficult control of the surrounding rock along the mining gateway under the dynamic mining condition of the contiguous seams in deep mine,the theoretical analysis and site exploration combined method was applied to analyze the deformation and stability lost causes of the mining gateway under the minin g condition of the contiguous seams in the deep mine. The analysis showed that the mine complicated high stress environment,the surrounding rock weakening,support me thod and irrational parameters of the gateway would be the key factors to cause the deformation and stability lost of the mining gateway. Based on the circumstances,with t he comprehensive application of the surrounding rock control principle with the“surrounding rock stress releasing,surrounding rock enhanced support,surrounding rock mod ified enhanced strength and surrounding rock stress migration" ,a surrounding rock control countermeasures combined with the' "bolt 1 steel mesh 1 shotcreting yield support + pre- stress anchor enhanced support + bolt 1 grouting modified + large diameter borehole pressure releasing' were provided according to the actual conditions. The site a pplication results showed that the surface deformation value of the gateway was not over 200 mm,cracks occurred in the gateway locally,individual bolt and anchor were fai lure and there was no floor heave and wall spalling occurred. During the gateway driving period,the max convergence between the two sidewalls was75 mm and the max C onvergence between the roof and floor was 56 mm. During the mining operation period of the coal mining face,the max convergence between the two sidewalls was 101 m m and the max convergence between the roof and floor was 77 mm.

     

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