基于覆岩移动规律的大孔径扇形高位钻孔瓦斯抽采技术

Gas Drainage Technology of Large Diameter Fan and High Level Boreholes Based on Overburden Movement Law

以沙曲矿为研究背景,依据工作面覆岩采后垮落形成的采动椭抛带和"竖三带"理论建立模型,研究了大孔径高位钻孔瓦斯抽采技术。通过分析煤岩层中卸压瓦斯移动分布规律得知,将钻孔终孔布置在裂隙带上半部和椭抛带的重叠区域内可取得最佳抽放效果,并给出了钻孔仰角及方位角取值范围的计算公式。24207工作面的抽采数据表明,钻场平均抽采浓度在42%左右,平均抽采纯量高达11.6 m3/min。

Taking ShaQu Coal Mine as the research background,it built the model based on the theory of elliptical parabolic zone and ＂three vertical belts＂ which formed as working face overburden collapsed after mining,then it studied the gas drainage technology of large diameter high level boreholes.Through analyzing the movement and distribution law of pressure relief gas in coal seams,it showed that the best drainage effect was obtained by putting terminal borehole into the overlay area of upper half fracture zone and elliptical parabolic zone,and the calculation formula of the borehole elevation angle and the range of azimuth value were given.The extraction data of the No.24207 working face showed that,the average extraction concentration of drilling field was about 42%,and its average extraction pure quantity could reached 11.6 m3/min.