大巷煤柱工作面过空巷矿压规律及控制技术

Mine pressure law and control technology of main roadway coal pillar working face passing through empty roadway

  • 摘要: 【目的】 由于矿井工作面布置方式的调整, 煤柱工作面经常会面临通过废弃巷道时覆岩顶板难以控制的情况。 【方法】 为解决这一问题, 以河南赵固二矿二盘区外侧煤柱工作面过空巷为工程背景, 采用理论分析、 数值模拟和现场试验等方法, 研究工作面与空巷覆岩破断组合结构, 模拟不同支护强度下顶板应力-位移全周期演化规律, 分析工作面矿压显现特征, 提出相应的控制技术。 【结果和结论】 结果表明, 基本顶不同破断形式对矿压显现特征影响显著, 关键块断裂位置可分为煤柱上方、 空巷上方和实体煤上方三种类型。 通过建立工作面过空巷力学模型, 研究基本顶超前破断力学机理, 基本顶受到空巷-煤柱-工作面支护系统支撑作用, 形成“砌体梁”稳定承载结构, 判定基本顶滑落失稳时空巷支护强度的临界值为 4.6 MPa。 数值模拟显示, 工作面超前支承压力与空巷应力集中产生的叠加效应对煤柱影响显著, 当工作面推进至距空巷 5 m 时,煤柱失稳破坏, 基本顶易发生超前破断。 在工作面过空巷过程中, 煤柱超前支承压力分布特征由“双峰型”转变为“孤峰型”。 不同支护强度下的顶板应力分布特征存在明显差异, 确定空巷支护强度为 4.5 MPa 能够防止基本顶超前破断。 最后, 在研究区二盘区外侧煤柱工作面采用“锚网索”支护方式对空巷顶板进行补强支护,过空巷期间液压支架工作阻力在研究区域处于安全范围内, 未发生顶板垮落和压架等事故, 解决了二盘区外侧煤柱工作面过空巷技术难题, 可为类似工作面提供参考依据。

     

    Abstract: Due to the adjustment of the layout of the mine working face, the coal pillar working face often faces the situation that the overburden roof is difficult to control when passing through the abandoned roadway. In order to solve this problem, taking the outer coal pillar working face of the second panel of Zhaogu No.2 Coal Mine in Henan Province as the engineering background, theoretical analysis, numerical simulation and field test are used to study the fracture combination structure of the working face and the overlying strata of the empty roadway, simulate the full-cycle evolution law of roof stress-displacement under different support strength, analyze the characteristics of mine pressure in the working face, and put forward the corresponding control technology. The results show that the different fracture forms of the main roof have a significant impact on the characteristics of mine pressure behavior. The fracture positions of the key blocks can be divided into three types : above the coal pillar, above the empty roadway and above the solid coal. By establishing the mechanical model of the working face passing through the empty roadway, the mechanical mechanism of the advanced breaking of the basic roof is studied. The basic roof is supported by the empty roadway-coal pillar-working face support system, forming a stable bearing structure of ' masonry beam '. The critical value of the support strength of the basic roof sliding instability space-time roadway is 4.6 MPa. The numerical simulation shows that the superposition effect caused by the advanced support stress of the working face and the stress concentration of the empty roadway has a significant influence on the coal pillar. When the working face is advanced to 5 m from the empty roadway, the coal pillar is unstable and the basic roof is prone to advanced breaking. In the process of working face passing through empty roadway, the distribution characteristics of advance support stress of coal pillar change from ' bimodal type ' to ' isolated peak type '. There are obvious differences in the distribution characteristics of roof stress under different support strength. It is determined that the support strength of the empty roadway is 4.5 MPa, which can prevent the basic roof from breaking in advance. Finally, the ' anchor net cable ' support method is used to reinforce the roof of the empty roadway in the outer coal pillar working face of the second panel. The working resistance of the hydraulic support during the empty roadway is within the safe range of the study area, and no accidents such as roof collapse and support crushing occur. The technical problems of the empty roadway in the outer coal pillar working face of the second panel are solved, which can provide reference for similar working faces.

     

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