芦岭矿近距离煤层重复开采下底板巷道稳定性研究

FLOOR ROADWAY STABILITY IN REPEATED MINING OF CLOSE DISTANCE COAL SEAMS IN LULING COAL MINE

以芦岭煤矿II82采区近距离煤层重复开采为工程背景,采用相似材料模拟、数值计算方法研究了近距离煤层重复开采过程中煤层底板应力的动态演化规律,并探讨底板巷道围岩应力及位移分布特征。结果表明:煤层底板应力分布具有明显的周期性波动现象,第1次开采时波动幅度最大,并且底板应力的集中及卸载程度与距离煤层的法向距离呈负相关性。针对此类巷道围岩裂隙发育、松动范围大的特点,提出以双层锚网喷支护为基础,结合注浆锚杆加固浅层破碎围岩、中空注浆锚索加固深部裂隙,充分调动围岩的自承能力,使支护体系与围岩形成承载整体。现场应用表明,该综合控制技术能有效控制巷道稳定,巷道在掘进1个月后基本趋于稳定,底鼓量不足100 mm。

Taking II82 district in Luling coal mine as the engineering background,the dynamic evolution rule of floor stress,the stress characteristics and displacement distribution of the floor roadway were analyzed by similar material simulation test and numerical simulation. The results show that the floor stress distribution has obvious cyclical fluctuations. The fluctuation range in first mining is the greatest,and the degree of the concentration and unloading of the floor stress and the normal distance from coal seam showed a negative correlation relation. Considering the characteristics of developed rock fracture and large range of loose circle,this paper,based on double-layer bolting-mesh-shotcrete support and combined with grouting anchor bolt reinforcing and hollow grouting anchor cable reinforcing methods,proposed that mobilizing the bearing capacity of surrounding rock can make the support system and surrounding rock as a whole to bear. The field test shows that this support scheme can effectively control the stability of roadway,the roadway was stable after one month and the amount of floor heave is less than 100 mm.