刀柱式采空区下坚硬顶板控制技术研究

Research on control technology of hard roof under wedge pillar type goaf

针对刀柱式采空区下坚硬稳定顶板初次垮落步距大、顶板突发大面积垮落容易引起安全生产事故的问题,采用理论分析和数值计算的方式分析了工作面初采期间顶板难以垮落的原因,得出顶板自稳性高、工作面倾斜长度小、盖山厚度小、刀柱式采空下不均匀应力等是影响刀柱式采空下工作面初采顶板难以垮落的主要原因。提出采用水力压裂对顶板进行弱化,压裂过程中采用后退式多分段压裂技术,压裂钻孔采用高位孔和低位孔交叉布置方式。现场应用结果表明,工作面初采期间顶板能够及时垮落,取得了良好的效果。

In view of the problem that the first collapse step of hard and stable roof under the knife pillar goaf is large,and the sudden large area collapse of roof is easy to cause safety production accidents,theoretical analysis and numerical calculation are used to analyze the reasons for the difficult collapse of roof during the initial mining of the working face,and it is obtained that the roof has high self stability,small working face inclination length,small cap thickness uneven stress under the goaf with cutter pillar is the main reason that affects the difficulty of roof caving in the initial mining of the goaf with cutter pillar.It is proposed to weaken the roof by hydraulic fracturing,adopt the retreating multi-stage fracturing technology in the fracturing process,and adopt the cross arrangement mode of high level hole and low level hole for fracturing drilling.The field application results show that the roof can collapse in time during the initial mining of the working face,and good results have been achieved.