郑州矿区“三软”煤层沿空掘巷锚网支护技术研究

Bolting and Mesh Support Technology of Roadway Driving Along Goaf in"Three Soft"Coal Seams in Zhengzhou Mining Area

沿空掘巷技术能够显著提高回采率,但是在工作面与相邻采空区之间的应力集中区域,巷道支护难度较高,导致该技术的应用受到一定限制。针对郑州矿区“三软”煤层沿空掘巷变形大、返修率高等问题,根据极限平衡理论,通过分析巷道围岩受力状态,提出了相应的锚网支护技术,得到留小煤柱的合理宽度为2 m。同时运用FLAC2D软件对31071工作面、31091工作面开采后的煤柱内侧向支承压力的分布规律进行了分析,探究了影响巷道围岩变形的关键因素,并设计了锚杆安装预应力为50 kN的锚网索联合支护方案,主要参数为顶锚杆规格20 mm×2400 mm,间排距750 mm×800 mm;帮锚杆规格20 mm×2000 mm,间排距700 mm×800 mm,并于31091工作面回风巷对该方案进行了工业性试验,试验结果反映出该方案应用效果良好。

The technology of driving along the goaf can significantly improve the recovery rate,but in the area of stress concentration between the working face and adjacent goaf,the difficulty of roadway support is high,which leads to the application of the technology is limited.Aming at the problems of large deformation and higher repairation rate of"three soft"coal seam in Zhengzhou Mining Area,according to the limit equilibrium theory,this paper analyzes the stress state of the surrounding rock of the roadway,puts forward the corresponding bolt net support technology,and obtains the reasonable width of the small coal pillar of 2 m.At the same time,FLAC2D sotware is used to analyze the law of the inner supporting pressure of the coal pillar after the mining of 31071 and 31091 working faces,to explore the key factors that affect the deformation of the surrounding rock of the roadway,and to design the combined support scheme of the anchor mesh cable with the installation prestress of the anchor rod of 50 kN.The main parameters are as follows:the specification of the top anchor rod is20 mm×2400 mm,the spacing between the rows is 750 mm×800 mm;the specification of the side anchor rod is20mm×2000 mm,the spacing between the rows is 700 mm×800 mm.The industrial test was carried out on the air return roadway of 31091 working face.The experimental results show that the scheme has a good effect.