大直径高位钻孔代替高抽巷治理采空区瓦斯研究

Study on Gas Control in Goaf by Large Diameter and High Level Borehole Replacing High Extraction Lane

为了解决高抽巷采掘交替紧张、回采成本高、施工周期长的难题,提出了用大直径高位钻孔代替高抽巷来抽采采空区瓦斯,并对钻孔合理布置层位进行了研究,以山西某矿68310工作面为工程背景,采用FLAC3D数值模拟和现场工业试验的方法进行分析研究。结果表明:模拟得到裂隙带高度为34.2 m,垮落带高度为12.5 m,与理论计算值基本一致;通过比较不同钻孔直径的应力集中系数和卸压范围,得到钻孔的最佳直径为0.4 m,最佳布孔间距为1 m。现场实测数据显示,大直径高位钻孔作用后上隅角瓦斯体积浓度降到约0.37%,回风巷瓦斯体积浓度降到约0.28%,抽采纯量与抽采浓度和高抽巷相当,有效解决了上隅角瓦斯超限的问题,同时证实了大直径高位钻孔代替高抽巷的可行性。

In order to solve the problems of tension in alternated stoping and extraction of high extraction lane,high recovery cost and long construction period,the large diameter and high level boreholes were proposed to replace high extraction lane to extract gas from goafs,and the reasonable layout of boreholes was studied.Taking the 68310 working face of a mine in Shanxi as the engineering background,the analysis was carried out by using FLAC3 D numerical simulation and field industrial tests.The results are concluded as follows.The simulated height of the fractured zone is 34.2 m,and the height of the caving zone is 12.5 m,which are basically the same as the theoretical calculation.By comparing the stress concentration factor and pressure relief range of different borehole diameters,the optimal borehole diameter is 0.4 m and the best hole spacing is 1 m.Field measured data shows that after the action of large diameter and high level borehole,the gas volume concentration in the upper corner drops to about 0.37%,and the gas volume concentration in the return airway drops to about 0.28%.The extraction purity and the extraction concentration are equivalent to those of high extraction lane,which effectively solves the problem of gas over-limit in the upper corner,and confirms the feasibility of large diameter and high level boreholes replacing high extraction lane.