孤岛工作面长水平深孔全长水力压裂卸压机理及多参量效果分析

    Full-length hydraulic fracturing pressure relief mechanism and multi-parameter effect anlysis of long horizontal and deep hole in isolated working face

    • 摘要: 为了解决深井孤岛工作面回采巷道面临的强动压问题,分析了孤岛工作面存在的工作面侧向采空区顶板悬顶、后方采空区侧顶板悬顶以及上部高位岩层结构悬顶3种类型,对深孔压裂类型进行了分析,提出了基于长水平孔的全长水力压裂布置方式,在某矿3203孤岛工作面进行了应用;通过在不同层位的目标岩层施工长水平孔压裂,实现了对于孤岛工作面强动压巷道卸压的全长处理。分别在采场和巷道进行矿压观测并选取评价指标,通过多参量、分阶段的分析,可以发现:这种卸压方式能在顶板构筑弱化条带,达到改善本工作面端头和采空区上方顶板空间结构形态、缩短工作面周期来压步距、降低工作面超前支承应力峰值的作用,从时间和空间上优化工作面超前区域应力场的分布状态,转移煤柱与巷道围岩的高应力,减小采动应力的影响,显著降低回采期间的巷道变形量,实现孤岛工作面的安全高效回采。

       

      Abstract: To solve the strong dynamic pressure problem faced by the roadways under deep island working face conditions, the three types of overhanging roof in the lateral mining area of the working face, overhanging roof in the side of the mining area of the working face and overhanging roof of the upper high rock structure under complex stress condition in the back mining roadway are analyzed. The type of deep hole fracturing is analyzed, and a full-length hydraulic fracturing arrangement based on long horizontal holes is proposed. It has been applied in 3203 island working face of a mine. By fracturing long horizontal holes in different layers of target rock, the full-length pressure relief treatment of strong dynamic pressure roadway in isolated island working face is realized. The mine pressure is observed in stope and roadway and the evaluation indexes are selected. Through multi-parameter and phased analysis, it can be found that: this pressure relief method can build a weakening band in the roof, achieve the effect of improving the spatial structure of the end of the working face and the roof above the goaf, shorten the working face periodic weighting distance, reduce the peak value of the leading supporting stress of the working face, optimize the distribution state of the stress field in the leading area of the working face from the perspective of time and space, transfer the high stress of the coal pillar and the surrounding rock of the roadway, and reduce the influence of mining stress. The amount of roadway deformation during mining is significantly reduced, and the safe and efficient mining of isolated island working face is realized.

       

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