自燃煤层综放开采区段煤柱留设方案优化研究

Optimization Study on Coal Pillar Retaining Scheme in Fully Mechanized Caving Mining Section of Spontaneous Combustion Coal Seam

沿空掘巷区段煤柱宽度确定是厚煤层综放工作面普遍面临的技术难题,留设窄煤柱可显著提高资源回采率。针对昌恒煤矿Ⅱ类自燃倾向煤层4103区段煤柱留设问题,采用理论分析和现场实测相结合的方法,建立了煤柱失稳尖点突变模型,结合稳定核区理论、极限平衡理论综合分析获得区段煤柱留设宽度。工业试验结果表明:①煤柱宽度a≤6.8m时,4103区段煤柱会发生失稳;②结合现场生产实际,最终确定4103区段煤柱最优宽度为7m;③位移监测显示,4103回风巷两帮最大位移量为520mm,顶底板最大位移量为280mm,满足巷道围岩稳定性要求;④监测结果表明,7m区段煤柱满足自燃煤层防漏风要求,未产生氧化自燃现象。研究结果可为类似条件矿井区段煤柱留设提供借鉴。

Determination of coal pillar width in gob side entry section is a common technical problem in fully mechanized caving mining working face of thick coal seam.Retaining narrow coal pillar can significantly improve the recovery rate of resources.Aiming at the problem of coal pillar retaining in 4103 section of class II spontaneous combustion coal seam in Changheng coal mine,the cusp catastrophe model of coal pillar instability was established by combining theoretical analysis with field measurement,and the reserved width of coal pillar in this section was obtained by comprehensive analysis of stable core area theory and limit equilibrium theory.The industrial test results are concluded as follows.Firstly,when the coal pillar width a≤6.8 m,the coal pillar in 4103 section is instabe.Secondly,combined with the actual production,the optimal width of coal pillar in 4103 section is determined to be 7 m.Thirdly,displacement monitoring shows that the maximum displacement of both sides of 4103 return air roadway is 520 mm,and the maximum displacement of roof and floor is 280 mm,which meets the stability requirements of roadway surrounding rock.Finally,the monitoring results show that the coal pillar with width of 7 mcan meet the requirements of air leakage prevention in spontaneous combustion coal seam,and no oxidation spontaneous combustion phenomenon occurs.The research results can provide a reference for retaining coal pillar in similar conditions of coal section.