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近距离煤层下行采动应力场分布规律与巷道合理位置研究

Research on the distribution law of downward mining stress field in close-distance coal seam and reasonable location of the roadway

  • 摘要: 上层位近距离煤层开采后,形成的残留煤柱和采空区将会影响下层位的巷道布置。以新柳矿231101工作面为工程背景,采用理论分析和数值模拟的综合研究手段,研究和分析了上煤层开采后采动应力场的应力演化规律,对下层煤巷道非对称变形破坏机理进行深入探究,从而得出下层煤巷道合理布置位置。研究结果表明:①上覆煤层开采改变巷道所处位置的主应力大小、主应力比值以及应力偏转角、应力矢量的变化是导致巷道呈非对称破坏的主要原因。②巷道在距离煤柱中心11 m处,巷道围岩最大主应力达到14.43 MPa,主应力比值为2.74,应力偏转角为52.33°,此时巷道处于较差的应力环境中,致使围岩产生蝶形破坏且蝶叶旋转至巷道顶板右侧,巷道顶板右侧易发生冒顶事故。③为使巷道处于相对稳定区域,依据3个主要影响因素将工作区域划分为4个分区,在考虑煤矿经济与安全因素后建议最佳布置区域为H–IV,主应力偏转角在0°~38°或45°~90°的范围内,通过综合分析对该巷道布置及支护提供合理建议,为类似工程条件提供了借鉴和参考。

     

    Abstract: The formation of residual coal pillars and void areas after mining of the upper seam close to the coal seam will affect the layout of the lower seam roadway. In this paper, taking 231101 working face of Xinliu Mine as engineering background, the comprehensive research means of theoretical analysis and numerical simulation is used to study and analyze the stress evolution law of mining stress field after overlying coal seam mining, and conduct an in-depth investigation on the asymmetric deformation damage mechanism of lower coal roadway, so as to arrive at the reasonable location of lower coal roadway layout. The research results show that: ① the overlying coal seam mining changes the principal stress magnitude, principal stress ratio and stress deflection angle at the location of the roadway, and the change of stress vector is the main reason for the asymmetric damage of the roadway. ② At 11 m from the center of the coal pillar, the maximum principal stress of the surrounding rock of the roadway reaches 14.43 MPa, the principal stress ratio is 2.74, and the stress deflection angle is 52.33°. At this time, the roadway is in a poor stress environment, resulting in butterfly-shaped damage of the surrounding rock and the rotation of the butterfly leaf to the right side of the roof of the roadway, and the right side of the roof of the roadway is prone to roofing accidents. ③ In order to make the roadway in a relatively stable area, this paper divides the working area into four zones based on three main influencing factors, and suggests that the best layout area is H–IV after considering the economic and safety factors of the coal mine, with the main stress deflection angle in the range of 0°−38° or 45°−90°.

     

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