State Key Laboratory of Water Resources Protection and Utilization in Coal Mining
China Energy Investment Grop Co., Ltd.
The National and Local Joint Engineering Laboratory of Internet Application Technology on Mine, China University of Mining and Technology
IoT Perception Mine Research Center, China University of Mining and Technology
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology

针对采动裂隙岩体在煤层采后长期演变过程中易发生降渗自修复的客观现象，以神东补连塔煤矿12401工作面和大柳塔煤矿52306工作面为典型试验区，开展覆岩不同区域裂隙岩体自修复规律的工程探测与理论研究，揭示了采后覆岩导水裂隙长期自修复过程的演变规律。结果表明，两矿试验面采动覆岩分别在采后15 a和7.3 a均获得了较好的自修复效果，在原先导水裂隙带范围出现导水的区域已明显减少，垮落带虽仍导水，但高度也已有所降低。通过将覆岩由原先导水变为隔水的自修复区段垂向长度占导水裂隙带高度的比值作为自修复率进行统计，得到12401试验面在开采边界附近及倾向中部覆岩中的自修复率已分别达到59.5%和53.5%，52306试验面在对应区域自修复率分别为25.8%和47.5%；因12401试验面采后年限更长、煤层埋深更大，其裂隙岩体自修复效果明显偏好。受覆岩纵向不同层位岩层赋存差异、横向不同区域初始垮裂程度的影响，自修复区域的分布常易呈现离散非连续性，其中间隔的未修复区一般对应于关键层或厚硬岩层位置，且采后年限越短、距开采边界越近，这种离散性越显著。采动裂隙岩体的自修复实际是多因素综合影响下的降渗演变过程，对于神东矿区开采条件，在煤层采后1.5～2 a时间内，是以应力压实作用引起的残余沉降为主导影响自修复进程，这在采区中部覆岩中体现相对显著；而后则一直以采动地下水与裂隙岩体或采空区CO2等气体发生的水–岩或水–气–岩相互作用为主导影响自修复进程，即相关作用过程产生的衍生物对裂隙的充填封堵效果以及裂隙面受冲蚀后粗糙度降低程度直接影响裂隙自修复效果或程度。因此，采后覆岩中是否长期存在水体渗流决定了裂隙岩体实现自修复的难易程度；神东多数矿井覆岩导水裂隙一般直接沟通第四系松散层或地表，且近年雨水充沛，这为采动覆岩中水–岩或水–气–岩相互作用产生及促进裂隙自修复提供了优越条件。

The objective phenomenon of seepage reduction and self-healing is easy to occur in the mining fractured rock mass after long-term evolution process of coal seam after mining. In survey of this phenomenon, taking the No. 12401 work face of Bulianta Coal Mine and the No. 52306 work face of Daliuta Coal Mine in Shendong as typical test areas, the engineering exploration and theoretical research on the self-healing law in different areas of overburden were carried out. The evolution law of long-term self-healing process of overburden after mining was revealed. The results show that the fractured overburden of the two coal mines had achieved good self-healing effects 15 years and 7.3 years after mining, respectively. The areas with water conduction within the original water-conducting fractured zone have been significantly reduced. Although the caved zone still conducts water, the height has also been reduced. By taking the ratio of the vertical length of the self-healing section in overburden from the original water diversion to the water isolation to the height of the water-conducting fractured zone as the self-healing recovery rate for statistics, it is obtained that the self-healing recovery rate of No. 12401 work face in the overburden near the mining boundary and in the middle of the dip has reached 59.5% and 53.5% respectively, and the self-healing recovery rate of 52306 work face in the corresponding area is 25.8% and 47.5% respectively. Due to that No. 12401 work face has mined for a longer time and has a larger coal seam burial depth, its self-healing effect of fractured overburden is obviously better. Affected by the occurrence difference of different strata in the vertical direction of the overburden and the initial damasge degree in different areas in the horizontal direction, the distribution of the self-healing area is often discrete and discontinuous, in which the interval of the unrepaired area generally corresponds to the position of the key stratum or thick and hard rock layer, and the shorter the post mining life and the closer to the mining boundary, the more significant the dispersion. The self-healing effect of mining fractured rock mass is actually a process of permeability reduction and evolution under the comprehensive influence of multiple factors. For the mining conditions in Shendong coalfield, the residual settlement caused by stress compaction plays a leading role in the initial process within 1.5 to 2 years after coal mining, which is relatively significant in the overburden in the middle of the mining area. Then, the self-healing process has been dominated by the water-rock or water-gas-rock interactions in goaf. That is, the filling and sealing effect of the derivatives produced in the relevant process on the fractures and the roughness reduction of the fracture surface induced by hydraulic erosion directly affect the self-healing results. Therefore, whether there is long-term water seepage in the overburden after mining determines the difficulty of self-healing of fractured rock mass. Water conducting fractures in the overburden of most mines in Shendong are generally directly connected to the Quaternary loose layer or surface, and in recent years, there is abundant rainfall, which provides superior conditions for the generation of water-rock or water-gas-rock interactions and the promotion of self-healing effect.

国家重点研发计划资助项目(2021YFC2902104)；国家自然科学基金资助项目(51604259)

李全生，鞠金峰，许家林，等. 神东矿区采动裂隙岩体自修复特征研究[J]. 煤炭科学技术，2023，51（8）：12−22

LI Quansheng，JU Jinfeng，XU Jialin，et al. Self-healing law of mining fractured rock mass in Shendong coalfield[J]. Coal Science and Technology，2023，51（8）：12−22