近距离煤层上行开采巷道合理布局研究

Reasonable layout of roadways for upward mining technology of close coal seams

以翟镇煤矿六采区二、四煤层上行开采为工程背景,为解决上层煤工作面巷道的合理布局问题,采用覆岩组合结构理论、现场实测和仿真模拟的手段,对下层煤采动形成的裂隙带综合形态特征及围岩集中应力分布进行重点研究。结果表明:在组合顶板条件下,裂隙带应是以岩层组为单位呈阶梯状向上发育的,现场实测得到的裂隙带发育高度也验证了上述形成机制;裂隙带空间形态呈现出一个向采空区内侧倾斜的拱形马鞍态,裂缝角为75°~78°;裂隙带内自下向上的分区破裂现象明显,上层二煤处于裂隙带上部的一般开裂区,在该区域布置回采巷道具有较大的可行性;数值模拟结果得到二煤层的断裂位置位于采空区侧3~5 m,内应力场分布范围在采空区侧6~10 m。在对下层四煤采后形成的裂隙带发育高度、空间形态、破裂分区以及集中应力分布进行综合研究的基础上,提出上行开采巷道内错式和外错式两种布局方案,有效避开了裂隙带及集中应力影响范围,取得了较好地现场应用效果。

In order to obtain the reasonable layout of roadways in the upper coal seam,the morphology characteristics of fractured zone and the concentrated stress distribution in surrounding rock induced by the mining of lower coal seam were studied with the methods of theoretical analysis,field testing and numerical simulation. This study was based on the upward mining of #2 and #4 close coal seams in No. 6 mining district of Zhaizhen mine. The results showed that the fractured zone was developed upward with the strata group as a unit under the condition of overlying composite strata structure and this forming mechanism was also verified in the field testing. The spatial morphology of fractured zone presented an irregular saddle shape tilted to the inside of the goaf with a boundary angle of approximately 75°–78°. The sub-regional rupture characteristic from bottom to top within the fractured zone was obvious. The upper #2 seam belongs to the general crack area located at the top of fractured zone. The roadway set in this areas is feasible. According to the results of numerical simulation,the broken position of the upper #2 seam was about 3–5 m on the goaf side,and the range of internal stress field was 6–10 m on the goaf side. Two schemes of roadway layout of inner stagger mode and outward stagger mode were proposed in upper coal seam based on the comprehensive study to the height,shape and sub-regional rupture characteristic of the fractured zone and the concentrated stress distribution. This layout effectively avoided the influence of fractured zone and concentrated stress field. The field application achieved good effect.