跨煤柱开采覆岩运动与载荷传递特征三维相似模拟研究

Three-dimensional similarity simulation research on the overburden movement and the characteristics of load transfer in crossing-pillar mining

  • 摘要: 下层煤工作面跨上覆遗留煤柱开采(简称“跨煤柱开采”)过程中,遗留煤柱承受高支承压力,可能导致下层煤工作面发生冒顶、压架、巷道损坏以及冲击地压等灾害。采用三维相似模拟试验研究跨煤柱开采时覆岩的运移规律和煤柱载荷传递特征。结果表明:随着遗留煤柱两侧工作面的开采,层间岩层应力分布发生显著变化,单侧采空时煤柱应力影响角约为7°,两侧采空时应力影响角增大至39°,工作面距离遗留煤柱约32 m时开始受煤柱集中应力影响;下层煤工作面进入煤柱下方开采后,采空区的煤柱逐渐发生屈服卸压,将覆岩载荷传递至工作面前方完整煤柱,形成载荷集中,在工作面推出煤柱5 m位置时,层间岩层断裂并诱发主关键层失稳,发生强矿压显现。

     

    Abstract: In the process of mining across the overlying residual coal pillars in the lower coal face (referred to as crossing-pillar mining), the residual coal pillars are subjected to high supporting pressure, which may lead to disasters such as roof caving, pressure crushing, roadway damage and coal burst in the lower coal face. A three-dimensional similarity simulation experiment was carried out to study the movement patterns of the overburden and the load transfer characteristics of the coal pillars during crossing-pillar mining. The results show that: With the mining of the working face on both sides of the residual coal pillar, the stress distribution of the interbedded rock strata changes significantly, the angle of influence of the coal pillar stress is approximately 7° in unilateral mining, and increases to 39° in two-sided mining, and the working face starts to be affected by the concentration of stress in the coal pillar when it is about 32 m away from the residual coal pillar. After the working face of the lower coal seam enters the mining below the coal pillar, the coal pillar in the goaf gradually yielded and was unloacled. This results in the transfer of the overburden load to the complete coal pillar in front of the working face, leading to stress concentration, which led to the main key stratum instability induced by the fracture of the interlayer rock layer when the working face was advanced to 5m from coal pillar, and the intense ground pressure appeared.

     

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