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为实现保护层开采工作面生产过程中瓦斯不超限,在分析工作面瓦斯来源的基础上,提出了保护层开采工作面竖向分层治理瓦斯的思路。根据相似模拟结果,分析了采空区瓦斯流动范围和流动范围内孔隙率、风阻分布特征。采用数值模拟分析了Y型通风、Y型通风+采空区埋管及Y型通风+采空区埋管+高抽巷+高位钻场3种瓦斯治理方式下采空区瓦斯体积分数场,结果表明:采空区瓦斯体积分数在竖直方向和水平方向均具有典型的递变特征,距工作面越远,距煤层越高,瓦斯体积分数越大;合适位置的煤层顶板高抽巷对抽采来自上邻近层的瓦斯具有较好的效果,试验条件下高抽巷抽采瓦斯量达到了总量的36.4%~63.6%;沿充填墙的采空区埋管不能完全拦截下层采空区进入沿空巷的采空区瓦斯,随沿空巷长度增加,瓦斯体积分数增大,建议沿空巷长度控制在250 m范围内。
In order to realize that gas does not exceed the limit in the production process of protective seam mining face, based on the analysis of gas sources in the working face, the idea of vertically stratifying gas in mining face of protective seam is put forward. Based on similar simulation results, the gas flow range and the porosity and flow resistance distribution in the gob area are analyzed. Numerical simulation is used to analyze the gas volume fraction field of the goaf under three kinds of gas treatment modes: Y-type ventilation, Y-type ventilation + goaf and Y-type ventilation + goaf buried + The results show that the gas volume fraction in the goaf has typical characteristics of gradient in the vertical and horizontal directions. The farther away from the working face, the higher the distance from the coal seam, the larger the gas volume fraction. Methane extraction from the adjacent layer has good effect. Under the experimental conditions, the amount of gas extracted from the high pumping tunnel reaches 36.4% ~ 63.6% of the total amount. The burying along the wall of the mined area can not completely intercept the bottom mined-out District into the goaf along the gob of gas, along with the gutter length increases, gas volume fraction increases, the proposed gob length control in the 250m range.