近距离高瓦斯煤层群倾向高抽巷抽采卸压瓦斯布置优化

倾向高抽巷作为一种治理卸压瓦斯的重要方法,其布置参数与抽采效果的匹配关系需要合理确定。针对典型的近距离高瓦斯煤层群开采条件,对采空区上覆岩层裂隙演化规律进行了研究,揭示了倾向高抽巷最佳布置位置在竖直方向上15倍采高、水平方向深入工作面约35 m处。据此,在24202工作面回风巷,以40°仰角起坡且垂直于回风巷轴线向顶板方向施工60 m,再沿倾向水平施工8 m来布置高抽巷。实际治理效果表明,单个倾向高抽巷的抽采半径为55~60 m,开采过程中有4~5个高抽巷处于瓦斯抽采活跃期,有效抽采总距离为500 m,平均抽采瓦斯总量25.22m3/min,占抽采总量的62.24%,实现了卸压瓦斯高效治理。

Layout parameter optimization of highly-located drainage roadway along seam for controlling gas with pressure relief from close-distance methane-rich seam group

Highly-located drainage roadway along seam is an important method for controlling pres-sure-relief gas, whose extraction efficiency is largely influenced by its layout parameters. In order to reasonably determine the relationship between the above two factors, the evolution rule of cracks in roof rocks has been simulated in the mining process of working face 24202 of close-distance methane-rich seam group. Results have shown that the maximum separation fracture zones lie at the point 15 times of the mining height in the vertical direction, and that appropriate broken fissures are 35 m away from the mining boundary along seam, which is the best layout position for highly-located drainage roadway. Therefore, highly-located drainage roadway should be set in the return airway of working face 24202 and, 60 m toward the roof by the dip angle 40°, and 8 m along the seam. Field industrial experiments have indicated that the drainage radius of single highly-located drainage roadway is 55-60 m, 4-5 high-ly-located drainage roadways are in the active gas drainage period, and total effective drainage dis tance is about 500 m. In addition, the overall gas drainage amount of highly-located drainage roadway is 25.22 m3/min on average, which takes up 60.24% of the total gas drainage in quantity. In summary, high efficiency in controlling of pressure-relief gas was realized.