高强度开采煤壁稳定性关键因素量化与危险性分级

Quantification of key factors and hazard classification of “coal wall” stability under high-intensity mining

  • 摘要: 针对高强度开采工作面易发生片帮从而制约工作面正常回采和智能化工艺预测与控制的难题,在已提出的高强度开采采场顶板岩层形成“组合短悬臂梁−铰接岩梁结构”基础之上,提出了影响煤壁稳定性的地质开采因素和4个开采技术因素,采用理论分析、数值模拟、物理相似试验相结合的方法,分析了高强度开采煤壁稳定性关键因素的影响。构建了煤体塑性屈服区短梁模型体,使用切比雪夫多项式对模型求解得到了复杂载荷作用下的挠曲线表达式,对表达式分析认为煤壁片帮受地质开采因素及开采技术因素影响较大。以曹家滩大采高工作面开采为工程背景,构建了开采技术因素正交试验,运用数值模拟和物理相似试验研究了各类开采技术因素对于煤壁稳定性影响的敏感度,提出以煤壁内塑性区面积与考察区域面积的塑性区占比η来衡量稳定性程度的指标,得出了各类因素与煤壁塑性区占比系数η的回归方程,据此定量得到了曹家滩煤矿大采高综放工作面煤壁稳定性与技术因素间关系式并给出了片帮风险预测危险性分级,结合物理相似试验验证了调整开采技术因素可在一定程度上控制煤壁发生片帮的范围和深度,为该矿大采高综放工作面煤壁稳定性智能化决策提供了理论依据,同时该研究手段也可用于其他工作面。

     

    Abstract: Aiming at the engineering problem of coal wall rib spalling under high-intensity mining that restricts normal mining and intelligent prediction and control, based on the proposed “combined short cantilever beam-articulated rock beam structure”, the geological mining factors and four mining technical factors that affect the stability of the coal wall were put forward. Using a method that combines theoretical analysis, numerical simulation, and physical similarity tests, the influence of key factors on the stability of coal wall in high-intensity mining was analyzed. A short beam model of the plastic yield zone of the coal wall was constructed, and a Chebyshev polynomial was constructed to solve the model and obtain the expression of the deflection curve under complex loads. The expression analysis shows that the coal wall rib spalling is greatly affected by geological mining factors and mining technology factors. Taking the Caojiatan large mining height working face as the engineering background, an orthogonal test of mining technical factors was constructed. Numerical simulation and physical similarity experiments were used to study the sensitivity of various mining technology factors to the stability of the coal wall. An index was proposed to measure the degree of stability based on the plastic zone ratio η between the area of the plastic zone in the coal wall and the area under investigation, and the regression equation between various factors and the plastic zone ratio coefficient η of the coal wall was derived. Based on this, the relationship between the coal wall stability and technical factors of the large mining height fully mechanized caving working face in the Caojiatan Coal Mine was quantitatively obtained, and the risk classification of the coal wall rib spalling was given. Combined with physical similarity experiments, it was verified that adjusting mining technical factors can control the range and depth of coal wall rib spalling to a certain extent, which provides a theoretical basis for the intelligent decision-making on coal wall stability in the fully mechanized caving working face with large mining height. This research method can also be used in other working faces.

     

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