禾二矿浅埋破碎顶板切顶成巷试验研究

针对浅埋薄煤层沿空留巷在工作面回采后垮落带内顶板不易垮落、沿空巷道动压显现剧烈的关键问题,通过关键理论分析、数值模拟、现场工程地质条件分析等手段,对浅埋深、薄煤层、破碎顶板条件下的切顶成巷技术开展研究,并在该条件下的禾草沟二号煤矿1105工作面回风顺槽进行现场应用。通过数值模拟,对比分析了切顶不充分和切顶充分时沿空巷道围岩应力分布及巷道围岩位移,结果表明:切顶充分时,采空区顶板对沿空巷道顶板动压影响大大减弱,巷道围岩变形较小,能够保证留巷效果。根据禾草沟二号煤矿浅埋、破碎顶板开采顶板运动模式和矿压显现特征,确定了切缝角度和恒阻锚索支护等关键参数,为浅埋、破碎顶板切顶卸压自动成巷的成功应用奠定基础,提出了切顶卸压自动成巷的预裂爆破参数设计、自动成巷支护技术;通过对禾草沟二号煤矿1105工作面回风顺槽留巷的工程地质条件分析,运用切顶成巷技术原理进行了留巷设计,并应用到现场,取得较好的应用效果。

Experimental study on gob-side entry formed by roof cut of broken roof at shallow depth of Hecaogou No. 2 Coalmine

For the key problem that the broken roof in caving zone of gob is not easy to fall and dynamic pressure of the gob-side entry is violent for the shallow depth and thin coal layer under broken roof, the technology of automatic gob-side entry formed by roof cut of shallow buried depth, thin coal layer, and broken roof is investigated through theoretical analysis, numerical simulation and engineering geological analysis. Through the numerical simulation, the distribution of stresses and the displacements of the surrounding rock are analyzed and compared when the roof cut is deficient or enough. The result shows that when the roof cut is enough, the effect of the roof of the goaf on the dynamic pressure of roadway roof is greatly weakened, and the deformation of the surrounding rock is small, which can guarantee the effects of the gob-side entry. And it is applied in the air-return way of 1105 working face of Hecaogou No.2 Coalmine. According to its motion patterns and behavioral characteristics of mine pressure, key parameters angle of seam and such as support of constant resistance cable are determined, and it lays a foundation for the successful application of the proposed technology of automatic gob-side entry formed by roof cut of shallow buried and broken roof. The relevant design pre-splitting blasting parameters and pressure relief are put forward. Through the analysis of engineering geological conditions of air return way of 1105 working face of Hecaogou No.2 Coal Mine, the key parameters are designed according to the technical principles of the gob-side entry formed by roof cut. The proposed technology is applied in practice, and good results are achieved.