采动裂隙带定向长钻孔布层优化及瓦斯抽采效果分析OA

This paper aims to address the poor gas extraction efficiency and imprecise stratigraphic selection in mining-induced fracture zones of high-gas mines.Taking the S206 working face of a mine in Shaanxi as the background,based on the"three-zone"model of overlying rock and the"O"-shaped zone theory,combining with FLAC3D numerical simulation,the study involves analyzing the evolution patterns of mining-induced fractures,optimizing the parameters for high-position directional long boreholes in the roof;and testing it on site.The results indicate that the height of collapse zone in this working face ran-ges from 6.32 to 12.96 m,while the fracture zone ranges from 28.49 to 42.43 m in height.The plastic zone exhibits a"ring-shaped strong development at the periphery and weak development in center",con-sistent with the"O"-shaped ring theory.After optimization,the vertical spacing of the boreholes from the roof is 13-25 m,and the horizontal spacing is 1.27-50 m.Within the fracture zone,the boreholes 1#-5#yields peak net gas flow rates of 4.5-6.8 m3/min,with a gas concentration at the upper corner of 0.3%-0.4%,residual gas content of 2.35 m3/t,and a recovery rate of 79.8%.In the non-frac-tured zone,the borehole No.6 yields a maximum flow rate of 3.01 m3/min,with a recovery rate of 44.8%,confirming the reasonable and effective stratigraphic selection.