低透气性煤层综放面高位钻孔层位布置研究

Research on Horizon Arrangement of High Level Borehole in Fully- mechanized Caving Face of Low Gas Permeability Coal Seam

郭村煤矿主采二1煤层低透气性、瓦斯含量高、采前不易预抽。为了预防工作面上隅角瓦斯异常涌出,提出了利用高位钻孔抽放采空区裂隙带富集瓦斯的方法。结合UEDC和Fluent数值模拟软件,模拟研究了采场上覆岩层中裂隙分布特征与采空区瓦斯运移规律,得出了距离上隅角平面约30m,距回采面垂高50-65m的范围内为游离瓦斯的富集区域,为采空区高位瓦斯抽放钻孔的布置提供了理论依据。同时,现场抽采试验表明,该抽采方法抽采效率高,有效抑制了上隅角瓦斯浓度超限。

Ⅱ1 coal seam of Guocun coal mine has the characteristics of low gas permeability,high gas content,not easy drainage before mining. In order to prevent abnormal gas discharge in upper corner,puts forward the method of using high level borehole discharging gas in goaf fissure zone. Combines UEDC and Fluent numerical simulation software,studies the distribution characteristics of fractures and the migration rules of goaf gas. Obtains the enriched area of free gas,which is at a distance about 30 m from the upper corner plane,and 50 - 65 m from working face vertical height. It provides a theoretical basis for designing high level gas drainage hole in goaf. At the same time,the field extraction test shows that the drainage methods has a high extraction efficiency,and effectively restrains the gas concentration overrun in upper corner.