采动垮裂岩体在煤层采后多年的长期演变过程中，常易发生导水能力逐步降低的自修复现象，研究其产生机制与规律对于实现矿区采损环境的生态再恢复意义重大。为了揭示神东矿区万利一矿煤层开采约10 a后垮裂岩体的自修复特征，采用钻孔原位探测方法对单一煤层采动和多煤层重复采动这2类典型条件下的覆岩垮裂特征及其自修复规律进行了观测研究。结果表明，历经8~12 a时间的演变，上覆垮裂岩体的自修复现象显著，表现为钻进冲洗液漏失量小、孔内水位下降缓的低渗透现象。采煤时覆岩的初始垮裂程度直接影响采后多年探测揭露的岩体自修复效果;从横向上看，开采边界附近为采动裂隙的显著发育区，因而其垮裂岩体自修复效果要低于盘区中部压实区的垮裂岩体;从纵向上看，垮落带中下部及导水裂隙带中上部自修复效果最好，而垮落带上部及其与导水裂隙带交界的过渡区由于普遍赋存有厚硬砂岩，因而其岩层垮落块度大、自修复效果相对偏低。煤层埋深越大，较大的支承压力更易促使超前煤岩体的压缩、以及边界附近显著发育裂隙的开度减小，这有助于促进裂隙的自修复;因而浅部矿区垮裂岩体实现自修复所需的年限更长。相比单一煤层开采，多煤层重复采动产生的二次活化作用会改变上煤层覆岩已有垮裂状态，还可能破坏在其中已发生的自修复进程;上下煤层采煤间隔时间越长，覆岩整体的自修复进程越慢、效果越差。

In the long-term evolution process after underground coal mining,the fractured rock mass is often prone to the phenomenon of self-healing that the water conductivity gradually decreases.It is of great significance to study the generation mechanisms and regular pattern for realizing ecological restoration of the mining-damaged surroundings.In order to reveal the self-healing characteristics of the mining-induced fractured rock mass in Wanli coal mine after 10 years of coal mining,the in-situ drilling detection method is used to observe the overburden fracture characteristics and self-healing degree under two typical conditions of single coal seam mining and multiple coal seam repeated mining.The results show that after 8-12 years of evolution,the self-healing phenomenon of overlying fractured rock mass is obvious,which is characterized by low permeability with small leakage of drilling flushing fluid and slow decline of water level in the borehole.The initial cracking degree of overburden during coal mining directly affects the self-healing effect of rock mass revealed by exploration for many years after mining.Horizontally,the mining fractures markedly develop in the rock mass near the mining boundary,so the self-healing effect of the cracked rock mass near the mining boundary is worse than that in the middle of the panel;and vertically,the self-healing effect in the middle and lower part of the caving zone and the middle and upper part of the fractured zone is the best,and due to the occurrence of thick hard sandstone in the upper part of the caving zone and its transition zone with the fractured zone the self-healing effect is relatively low.The larger the buried depth of the coal seam,the greater the abutment pressure,which is easier to promote the compression of the advanced rock mass,and the decrease of the opening of the obvious cracks near the boundary,which is helpful to promote the self-healing of the cracks.Therefore,the self-healing of the fractured rock mass in the shallow mining coalfields needs a longer time.Compared with single coal seam mining,the secondary activation caused by repeated mining of multiple coal seams will change the existing cracking state of the overlying strata of the upper coal seam,and may also destroy the self-healing process that has occurred in it.The longer the mining interval between the upper and lower coal seams,the slower the self-healing process of the overlying strata as a whole,and the worse the effect.

1 万利一矿试验区地质开采条件

   1.1 试验区概况

   1.2 钻探试验区选取

   1.3 钻探区采后导水裂隙初始发育情况

2 钻孔探测结果与分析

   2.1 T1钻场——单一煤层采动覆岩探测

   2.2 T2钻场——多煤层重复采动覆岩探测

3 采后10 a垮裂岩体的自修复特征讨论

4 结论