采动影响下巷式残采区上行开采可行性判定

Feasibility on the upword mining of the left-over coal above goaf with roadway mining method considering mining effect

为了揭示巷式残采区上行开采层间岩层破坏失稳机理,考虑上方煤层的采动影响,立足于岩层结构的力学特性,建立了均布荷载下连续深梁力学结构模型。结合虎龙沟煤矿开采实际,对8号煤巷式残采区层间岩层稳定性进行理论计算分析,同时FLAC3D数值模拟分析层间岩层的应力场和位移场分布特点。研究结果表明:当采用上行开采时,在巷式残采区相邻煤柱之间,"内应力拱"会在悬空的顶板中出现,且在整个采场上方顶板中形成更大范围的"外应力拱",则巷式残采区上覆顶板存在稳定的层间控制岩层,能够有效避免集中应力破坏层间岩层,抑制上覆岩层破坏高度的扩展。若在采场上方形成较大范围的"位移拱",则说明层间岩层破断并没有形成层间控制层,不能上行开采。可见稳定的层间控制层对上行开采全局起着决定性的作用。

In order to reveal breakage mechanism of key strata in goaf of roadway mining zone, considering rock structure and mining effect, continuous deep beam model under uniformly distributed load is established and determination theory and method of feasibility on the upward mining is proposed. The key strata mechanical properties of 8 号 coal seam is analyzed with theoretical calculation and numerical simulation analysis in Hulonggou coal mine.And FLAC3 D numerical simulation analysis between the layers of rock stress field and displacement field distribution characteristics. The results show that a local scope of ＂internal stress arch＂ appear between adjacent coal pillars in the key strata after mining lower coal. If a wider range of ＂external stress arch＂ appear in the whole range of stope, there is stabilized key strata in the roof of roadway mining and the key strata effectively avoid damage of rock stratum from stress concentration, restrain the expansion of the overburden failure height. If a wider range of ＂displacement arch＂ appear in the whole range of stope, the rock stratum is destroyed and upward mining is impracticable.so the stabilized key strata plays a determinative effect for upward mining.