深孔预裂对初采面老顶极限跨距的影响研究

初采工作面老顶大多强度高、厚度大、完整性好,回采期间易造成悬顶距离较大,给安全生产带来隐患.为防治初采面老顶大面积悬顶产生的一系列问题,初采前在切眼处布置预裂炮孔,利用深孔预裂的方法破坏老顶的完整性,达到减小老顶来压强度和极限跨距的目的.本研究依据老顶岩梁的力学模型特点,从理论上比较深孔预裂前后老顶步距变化情况,发现采用深孔预裂后老顶极限跨距是未处理老顶极限跨距的0.82倍,经与潞安集团常村矿应用现场实测数据对照,具有较好的一致性.从理论和实测数据可知,深孔预裂能减小老顶极限跨距.

Effect of Deep Hole Presplit to Main Roof Limited Span in First Mining Face

The main roofs of first mining face are mostly characteristic of high strength, large thickness and good in- tegrity,which may produce long hanging distance in mining and bring a potential threat to safety production. To pre- vent a series of problems caused by large overhang roof,this study used the deep hole presplit technology to damage the integrity of main roof beforehand, reducing the pressure strength and limited span. Based on the mechanical char- acteristics of main roof,this paper compared the changes of limited span between unhandled and handled main roof, and obtained theoretical conclusion that the limited span of main roof with deep hole presplit was 0.82 times of the limited span of unhandled main roof;and in contrasting the theoretical data with the field data in Changcun Coal Mine of Lu＇an Group,a high consistency was detected between the two. This contrastive result shows that deep hole pres- plit technology can shorten the limited span of main roof.