马蹄沟煤矿末采工作面切眼坚硬顶板弱化关键技术

Weakening key technology of the cut-hole hard roof at the final mining face in Matigou Coal Mine

为解决马蹄沟煤矿3506末采工作面切眼坚硬顶煤、顶板难以垮落,安全隐患突出的技术难题,基于爆炸应力波与爆生气体共同作用理论,考虑切眼掘进及钻孔施工扰动影响,推导了爆源周围岩体破碎区与裂隙区范围计算公式,确定了炮孔长度及线装药密度等关键爆破参数。针对顶煤瓦斯易汇聚于炮孔末端这一客观现象,提出了一种矿用爆破装药消焰被筒结构,减小了爆破火花,增加了爆破安全冗余度。最后,通过对切眼液压支架阻力及顶板锚索受力情况进行监测分析,发现工作面切眼顶板预裂爆破后液压支架阻力较爆破前有所增大,锚索轴力显著减小,表明顶板岩体整体性得以有效破坏,切眼坚硬顶板弱化效果良好。

In order to solve the technical problems of hard roof coal in the 3506 final mining face of the Matigou Coal Mine,the roof is difficult to collapse,and the safety hazard is prominent.This paper is based on the theory of the interaction between the explosion stress wave and the explosion gas,and considers the cut-hole tunneling and drilling construction disturbance,the calculation formula of the range of the rock mass fragmentation area and the fracture area around the blast source is deduced,and the key blasting parameters such as the length of the blast hole and the density of the line charge are determined.Aiming at the objective phenomenon that the top coal gas is easy to gather at the end of the blast hole,a flame-eliminating sheathed structure of mine blasting charge is proposed,which reduces the blasting spark and increases the blasting safety redundancy.Finally,by monitoring and analyzing the resistance of the cut-hole hydraulic support and the force of the roof anchor cable,find that after the presplitting blasting of the cut-hole roof of the working face,the resistance of the hydraulic support is increased compared with that before the blasting,and the axial force of the anchor cable is significantly reduced,indicating that the integrity of the roof rock mass is effectively destroyed,and the cut-hole hard roof has a good weakening effect.