基于不同漏风源浅埋煤层采空区自燃“三带”分布规律研究

Study on distribution law of spontaneous combustion“three zones”in goaf of shallow-buried coal seam based on different air leakage sources

为解决浅埋自燃煤层采空区因地表及工作面漏风而自燃的难题,以沙坪煤矿1818工作面为例,利用SF_(6)示踪法检测采空区地表漏风通道和风速,利用FLUENT数值模拟分析不同漏风源采空区自燃“三带”分布的特征,并通过现场束管测试结果对比分析浅埋煤层采空区地表漏风对自燃“三带”分布的影响,同时限定工作面最小推进速度,确保工作面的安全生产。研究结果表明:地表漏风风速为0.06~0.30 m/s,漏风通道多且复杂;相比于工作面单一漏风源,有地表漏风存在时,自燃危险性加大;限定工作面最小推进速度为1.24 m/d。因此,多漏风源煤层开采条件下自燃“三带”分布的确定对浅埋藏自燃煤层采空区遗煤自燃预测预报及预防工作具有重要的指导和借鉴意义。

In order to solve the problem of spontaneous combustion in the goaf of shallow-buried spontaneous combustion coal seam due to the air leakage on the ground surface and working face,taking the 1818 working face of Shaping Coal Mine as an example,the SF_(6) tracer method was used to detect the surface air leakage channel and wind speed in the goaf.The FLUENT numerical simulation analysis was used to analyze the characteristics of the spontaneous combustion“three zones”distribution in the goaf under different air leakage sources,and the influence of surface air leakage in the goaf of shallow-buried coal seam on the distribution of spontaneous combustion“three zones”was compared and analyzed through the on-site beam tube test results.At the same time,the minimum advancing speed of the working face was limited to ensure the work safety of the working face.The results showed that the wind speed of surface air leakage was 0.06~0.30 m/s,and there were many and complicated air leakage channels.Compared with the single air leakage source on the working face,the risk of spontaneous combustion increased when there was the surface air leakage.The minimum advancing speed of the working face was limited to 1.24 m/d.Therefore,the determination on the distribution of the spontaneous combustion“three zones”in coal seams with multiple air leakage sources has important guidance and reference significance for the prediction,forecast and prevention on the spontaneous combustion of residual coal in the goaf of shallow-buried spontaneous combustion coal seams.