切顶沿空留巷采空区自燃带分布特征及喷涂堵漏防灭火技术

Distribution characteristics of spontaneous combustion zone and spray plugging fire prevention and extinguishing technology in goaf of roof cutting and gob-side entry retaining

切顶沿空留巷敞开式采空区自然发火严重,目前尚不明晰该条件下的自然发火特征,故难以采取有效的防治措施。为解决上述难题,构建切顶沿空留巷采空区三维流场PFC-FLUENT耦合计算模型,分析切顶沿空留巷工作面不同通风方式下采空区自燃带分布特征,在此基础上提出切顶沿空留巷阶段性喷涂堵漏技术。研究结果表明:切顶后形成的敞开式采空区与沿空留巷直接贯通,采空区内的气体成分与气体分布发生明显变化。“Y”型通风条件下,切顶沿空留巷采空区自燃带宽度和深度明显增大,且在沿空留巷侧出现条带状自燃带。“W”型通风有利于降低工作面向采空区的漏风,但在切顶沿空留巷尾段开切眼附近出现明显的自燃带,且该自燃带不会随着工作面的推进进入窒息带。对沿空留巷成巷稳定区进行喷涂堵漏能够显著降低采空区的漏风量,改变采空区内部的压力场,减小上隅角一侧采空区内部的自燃带深度和宽度,降低采空区自然发火的危险性。

The spontaneous combustion in the open goaf of roof cutting and gob-side entry retaining is severe, and the characteristics of spontaneous combustion under this condition are not clear, so it is difficult to take effective control measures. In order to solve this problems, the PFC-FLUENT coupling calculation model of three-dimensional flow field in the goaf of roof cutting and gob-side entry retaining was constructed, the distribution characteristics of the goaf spontaneous combustion zone in the working face under different ventilation methods were analyzed, and then the phased spray plugging technology of roof cutting and gob-side entry retaining was proposed. The results have shown that the open goaf formed by cutting roof was directly connected with the gob-side entry, the gas composition and gas distribution in the goaf were significantly changed. Under the condition of “Y” type ventilation, width and depth of spontaneous combustion zone in goaf increased obviously, and belt spontaneous combustion zone appeared along the gob-side entry. “W” type ventilation was beneficial to reduce the air leakage into goaf, but there was an obvious spontaneous combustion zone that was near the open-off cut at the end of the gob-side entry and would not enter the suffocation zone with the advance of the working face. Plugging the stable area of gob-side entry could significantly reduce the air leakage in goaf, change the pressure field inside goaf, reduce the depth and width of spontaneous combustion zone inside goaf at the upper corner, and reduce the risk of spontaneous combustion in goaf.