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坚硬顶底板煤层煤柱失稳机理及控制技术研究

Study on instability mechanism and control technology of coal pillar in hard roof and floor coal seam

  • 摘要: 针对坚硬顶底板煤层综采工作面区段煤柱失稳问题, 以新疆某矿井1016工作面轨道运输平巷区段煤柱为工程背景, 通过理论分析、数值模拟及现场试验的研究方法, 分析了工作面覆岩运移规律, 提出了坚硬顶底板条件下煤柱内能量积聚成因, 研究了煤柱内弹性能密度与第一、第三主应力间的函数关系, 根据弹性力学得出了不同应力集中系数下煤柱内应力及能量分布规律。研究结果表明: 上工作面开采后, 厚硬基本顶会形成“长悬臂梁”结构, 造成煤柱内载荷升高; 由于煤体强度与顶底板强度相差较大, 造成外界输入“顶板–煤柱–底板”系统的能量主要以弹性应变能形式在煤柱内积聚; 区段煤柱中任意位置处弹性应变能与第一、第三主应力之间可大致视为正相关关系; 煤柱内弹塑性区交界区域为煤柱内弹性应变能主要积聚部位; 掘巷后煤柱应力环境的恶化、煤柱内积聚能量的释放是煤柱发生变形破坏的主要原因; 提出了“顶板密集钻孔+煤柱钻孔卸压+加强支护”防治技术, 现场应用效果显著。

     

    Abstract: Aiming at the problem of coal pillar instability in the fully mechanized mining face section of hard roof and floor, taking the section coal pillar of the track haulage roadway in the 1016 working face of a certain mine in Xinjiang as the engineering background, through theoretical analysis, numerical simulation and field test research methods. The movement law of overlying strata in the working face was analyzed. The causes of energy accumulation in the coal pillar under the condition of hard roof and floor were proposed. The function relationship between the elastic strain energy density in the coal pillar and the first and third principal stresses was studied. According to the theory of elasticity, the stress and energy distribution laws in the coal pillar under different stress concentration coefficients were obtained. The research shows that after the upper working face is mined, the thick and hard basic roof will form a "long cantilever beam" structure, causing the load in the coal pillar to increase. Due to the significant difference in strength between the coal mass and the roof and floor, the energy input from the outside into the "roof-coal pillar-floor" system mainly accumulates in the coal pillar in the form of elastic strain energy. The elastic strain energy at any position in the section coal pillar can be roughly regarded as a positive correlation with the first and third principal stresses. The junction of the elastic and plastic zones in the coal pillar and the surrounding area are the main parts where the elastic strain energy is accumulated, while the accumulation degree of elastic strain energy in the broken zone of the coal body is relatively small. The deterioration of the stress environment of the coal pillar after the roadway is excavated, the release of the accumulated energy in the coal pillar is the main reasons for the deformation and failure of the coal pillar. The prevention and control technology of "intensive drilling in the roof + coal pillar drilling pressure relief + strengthening support" was proposed, and the field application effect was obvious.

     

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