远距离抽采条件下采空区煤自燃区域分布规律

针对塔山煤矿8204-2工作面上方地形复杂、只能在回采起点集中布置钻孔抽采瓦斯的特殊情况,利用数值模拟软件研究分析回采期间不同回采长度和不同注氮量下采空区氧气摩尔浓度分布情况,确定该特殊情况下采空区自燃"三带"和煤自燃危险区域。结果表明:远距离抽采瓦斯使煤自燃危险区域变大;随着回采长度的增长,自燃带逐渐变宽;当回采长度为50 m时,自燃带宽度增宽速率突然变大,进风侧自燃带变宽幅度与回采长度变长幅度比例比回采长度为30~50 m时高出180%,回风侧相应宽度则高出140%,遗煤自燃危险性变大;注氮可大幅度减小采空区煤自燃危险区域。

Distribution Law of Spontaneous Combustion Danger Zone of Coal in Goaf Under Long Distance Extraction

For the special case above the working face of Tashan Coal Mine, the numerical simulation software was used to study the distribution of oxygen molar concentration in the goaf under different mining distances and different amounts of nitrogen injection and determine the coal spontaneous combustion danger zone in the goaf. Results show that long-distance extraction of gas makes the coal spontaneous combustion danger zone larger. As the mining distance increases, the spontaneous combustion danger zone gradually widens. When the mining distance is 50 m, the rate of widening the spontaneous combustion zone suddenly becomes larger. The ratio of the width of the spontaneous combustion zone on the inlet side to the length of mining distance is 180% higher than that of the mining distance of 30 m to 50 m, and the return side is 140% higher, causing larger risk of spontaneous combustion of coal;nitrogen injection can greatly reduce the coal spontaneous combustion danger zone in the goaf.