南梁煤矿多煤层开采地下水系统演化规律

煤层开采对所在矿区地下水系统有着重要影响。以往研究单煤层开采对地下水系统的影响较多,而对多煤层的影响研究甚少,特别对于我国西部缺水矿区。以南梁煤矿为例,运用地下水系统演化理论和岩石力学模拟等,对该矿井水文地质结构、矿井涌水变化规律、矿井地下水流场演变、矿井地下水化学成分变化等方面进行了综合分析研究,重构了多煤层开采条件下南梁矿井地下水系统流动模型,初步揭示了矿井水化学成分的演化机理。研究结果表明,2^-2煤单煤层开采时,顶板导裂带的最大发育高度为42.1 m,而2^-2和3^-1煤层重复开采时则增大为83.1 m,相应地应力、位移、塑性区范围后者也比前者增大许多。这揭示出多煤层重复采动明显增大了顶板导裂带的发育高度,加剧了矿井水文地质结构变异,进一步地,导水裂隙带改变了天然地下水渗流路径,沟通了不同含水层之间的水力联系,增强了地下水流动速度和水文地球化学作用,整体扩大了地下水流动系统的规模,从降雨入渗→导裂带渗流→各煤层涌水→井底水仓排水构成了一个自然-人工复合地下水流动模式。研究成果可以为南梁煤矿的矿井水害防治及水资源高效利用提供科学依据,也为类似矿区提供研究参考。

Evolution law of groundwater system with multiple seams mining in Nanliang Coal Mine

Coal mining has an important impact on the groundwater system in the mining area.In the past, more research was distributed on the impact of single coal seam mining on the groundwater system, while the impact on multiple coal seams was rarely studied, especially for water-deficient mining areas in western China.Taking Nanliang Coal Mine as an example, groundwater system evolution theory and physical mechanics simulation method, etc.were used to study the mine hydrogeological structure, mine water inrush change law, mine groundwater flow field evolution, mine groundwater chemical composition change, etc., the groundwater flow system model of Nanliang Coal Mine was reconstructed under the condition of multi-coal mining, and the evolution mechanism of the chemical composition of mine water was initially revealed.The research results showed that when the 2-2 coal seam was mined, the maximum development height of the roof cracking zone was 42.1 m, while when the 2-2 and 3-1 coal seams were repeatedly mined, it increased to 83.1 m.The corresponding stress, displacement, and plastic zone range of the latter was also much larger than the former.This revealed that the repeated mining of multiple coal seams significantly increased the development height of the roof cracking zone, aggravated the variation of the mine's hydrogeological structure, and further, the water-conducting fracture zone changed the natural groundwater seepage paths and communicated the hydraulic connection between different aquifers.As a result, the groundwater flow rate and hydrogeochemical effects were enhanced, and the scale of the groundwater flow system was expanded as a whole, so a natural-artificial composite groundwater flow pattern from rainfall infiltration→seepage in the fracturing zone→water inrush from each coal seam→drainage from the bottom sump was formed.The research can provide a scientific basis for the prevention and control of mine water hazards and the efficient use of water resources in Nanliang Coal Mine, as well as a reference for similar mining areas.