Study on the influence of ventilation methods on coal spontaneous combustion in gob-side entry retaining goaf areas
GUO Jun;WANG Lei;DU Wentao;LIU Yin;CHEN Changming;ZHANG Kefeng;LI Dailin
沿空留巷开采条件下采空区气体分布特征易受通风方式影响,煤自燃隐患位置难以精准掌握。针对上述问题,以甘肃某矿8521工作面为研究背景,利用Fluent软件构建了沿空留巷采空区物理模型,分析了沿空留巷采空区煤体孔隙率,对比了“W”型通风与“Y”型通风(一进两回、两进一回)方式下采空区漏风流场及氧浓度分布特征。结果表明:沿空留巷采空区煤体孔隙率整体呈“铲状”分布(即边缘高、中部低)并逐步向采空区收缩;当矿井供风量及速率一定时,沿空留巷采空区漏风速率受通风方式影响,与进风巷数量呈正相关;采空区关键漏风位置多为沿空侧风流交汇处,该位置的漏风速率受压差影响;采空区漏风流场的差异导致各通风方式下的氧浓度及氧化升温带的分布特征不同,“W”型通风方式下采空区浅部、深部气体整体均呈扇形运移,氧化升温带靠近沿空留巷且呈“√”分布,氧化升温带面积占已采区域面积的38.1%;综合对比采空区关键漏风位置、氧化升温带分布特征及防灭火难度等方面,得出“W”型通风更有利于采空区煤自燃防治。
Under gob-side entry retaining mining conditions, the gas distribution characteristics in the goaf are easily affected by the ventilation methods, making it difficult to accurately identify the locations of coal spontaneous combustion hazards. To address this issue, the 8521 working face of a mine in Gansu was used as the research background. A physical model of the gob-side entry retaining goaf was constructed using Fluent software. The study analyzed the coal body porosity in the goaf and compared the leakage airflow field and oxygen concentration distribution characteristics under "W"-type ventilation and "Y"-type ventilation (single entry, two returns, and two entries, one return) methods. The results showed that: the coal body porosity in the gob-side entry retaining goaf generally presents a "shovel-shaped" distribution, with higher porosity at the edges, lower in the center, gradually narrowing towards the goaf. When the ventilation volume and rate of the mine are fixed, the leakage airflow rate in the gob-side entry retaining goaf is influenced by the ventilation method and is positively correlated with the number of intake lanes. The key leakage points in the goaf are mainly located at the intersections of the side airflow, and the leakage rate at these points is influenced by the pressure difference. The differences in the leakage airflow field in the goaf lead to different oxygen concentration and oxidation heating zone distribution characteristics under each ventilation method. Under the "W"-type ventilation method, the gas in both the shallow and deep parts of the goaf migrates in a fan-shaped pattern. The oxidation heating zone is closer to the gob-side entry retaining and is distributed in a "√" shape. The area of the oxidation heating zone accounts for 38.1% of the mined area. A comprehensive comparison of the key leakage points in the goaf, oxidation heating zone distribution, and firefighting difficulty indicates that "W"-type ventilation is more beneficial for preventing and controlling coal spontaneous combustion in the goaf.
coal spontaneous combustion;gob-side entry retaining;goaf;ventilation methods;oxygen concentration;"three zones" of coal spontaneous combustion;air leakage patterns
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会