低位巷掘进过程对下伏煤层瓦斯抽采影响分析及工程应用

Influence of low drainage roadway driving on lower coal seam gas extraction and its engineering application

高瓦斯煤层群开采过程中往往伴随着各类煤与瓦斯突出问题,其中瓦斯赋存规律及涌出特征的难以把握更是制约着煤矿的安全高效开采。为有效解决高瓦斯煤层群环境下的煤层透气性低及瓦斯含量大等问题,文中以华阳集团平舒煤矿为试验背景,采用高低位瓦斯协同抽采技术,在工作面上方布置高低位巷道来对煤层进行卸压以及瓦斯预抽,并通过数值模拟方法重点分析了低位巷与下伏煤层的垂直间距大小对煤层应力释放和变形特征的影响。结果表明:低位巷的掘进会对15~#煤层造成非均匀性扰动,通过模拟得到低位巷与煤层的垂直距离为5 m时,最大应力释放量约为13.90%,最大变形量为3.20%;提出了低位巷的合理布置参数,即在距15~#煤层上方5 m的砂质泥岩中布置巷道宽度为5 m,巷道高度为2.6 m的低位巷;通过对生产、检修期间工作面上隅角和回风巷的瓦斯浓度进行长期监测,有效验证了该技术在治理本煤层及邻近层瓦斯的可行性。

The mining process of high gas seam group is often accompanied by various kinds of coal and gas outburst problems,among which the difficulty of grasping the occurrence law and emission characteristics of gas restricts the safe and efficient mining of coal mines.In order to effectively solve the problems of low permeability and high gas content in the environment of high-gas coal seam group,this paper takes Pingshu Coal mine of Huayang Group as an experimental subject,adopts the high-low gas co-extraction technology,and arranges the high and low-level roadway above the working face to relieve the pressure of coal seam and pre-extract gas.The influence of the vertical distance between low level roadway and underlying coal seam on the stress release and the deformation characteristics of coal seam are analyzed by numerical simulation.The results show that the driving of low-level roadway will cause non-uniform disturbance to 15coal seam.When the vertical distance between low-level roadway and coal seam is 5 m,the maximum stress release is about 13.90%and the maximum deformation is 3.20%.The reasonable layout parameters of low-level roadway are proposed,that is,the low-level roadway with a width of 5 m and a height of 2.6 m is arranged in sandy mudstone 5 m above 15coal seam.Through long-term monitoring of gas concentration in the corner of working face and return air lane during production and maintenance,the feasibility of this technology in treating gas in the coal seam and adjacent layers is verified effectively.