采空区瓦斯抽放钻孔终孔范围确定方法研究

Study on Determination Method of Borehole End Scope for Gas Drainage Borehole in Goaf

为提高采空区瓦斯抽放效率,通过对覆岩采动裂隙椭抛带和"竖三带"理论的分析,建立了数学模型,并分析了采空区瓦斯运移形态,提出了采空区瓦斯抽放钻孔终孔应布置在内外抛椭带之间,同时也应位于该区域上覆岩层的裂隙带下部及规则冒落带上部。温庄矿采用此方法改造了150301工作面采空区瓦斯抽放钻孔,结果使瓦斯抽放量达到7.2 m3/m in,且工作面风量由原来的2 050 m3/m in降低至1 500 m3/m in,解决了上隅角瓦斯超限的难题,保证了生产的正常进行。

In order to improve the gas drainage efficiency in the goaf,with the analysis on the theory of the elliptical parabolic zone and ＂the vertical three zones＂,a mathematic model was established and the gas migration pattern in the goaf was analyzed.The paper proposed that borehole end of the gas drainage borehole in the goaf should be laid out at the location between the inner and outer of the elliptical parabolic zone and also should be located at the crack zone bottom of the overburden strata and at the top of the normal falling zone in that area.The method was applied in Wenzhuang Mine to reconstruct the gas drainage boreholes in the goaf of No.150301 coal mining face.The results showed that the gas drainage value was reached to 7.2 m3/min and the ventilation quantity of the coal mining face was reduced from the previous 2 050 m3/min to 1 500 m3/min which could solve the gas over limit problem in the top corner and could ensure the mine production to be normally operated.