Study on the Formation Mechanism of Gob Water Accumulation Based on Crossflow Conditions

针对深部煤层开采中越流作用下采空区大量积水问题，以西部某矿为研究对象，通过水文地质调查与数值模拟相结合系统揭示了多含水层协同作用下采空积水的形成机理。研究表明：煤层开采形成的采动裂隙首先沟通侏罗系含水层，使其成为主要充水水源并持续增强主导作用；侏罗系中统含水层水位下降形成以采空积水区为中心的地下水降落漏斗，导致与白垩系含水层水压差增大；采动裂隙与先天构造裂隙带叠加后形成白垩系含水层越过弱透水层的垂向越流补给通道，促使白垩系水成为采空区间接补给水源。研究成果对保障西部地区类似矿井的水害防治及安全开采提供了理论支撑。Aiming at the problem of large amount of water accumulation in the mining airspace under the action of crossflow in deep coal seam mining, a mine in the west is taken as the research object, and the formation mechanism of gob water accumulation under the synergistic action of multiple aquifers is systematically revealed through the combination of hydrogeological investigation and numerical simulation. The study shows that: the mining fissures formed by coal seam mining firstly communicate with the Jurassic aquifer, making it become the main water filling source and continue to enhance the dominant role; the water level of the middle Jurassic aquifer drops to form a groundwater descent funnel centered on the gob water accumulation, resulting in the increase of the difference in the water pressure between the waterlogged area and the Cretaceous aquifer; the mining fissures are superimposed on the tectonic fissure zones to form a vertical crossflow recharge channel for the Cretaceous aquifer to cross over weakly permeable layers, prompting the Cretaceous water to become a water recharge channel, which will lead to the formation of the water from the Cretaceous aquifer. The combination of the mining fissure and the innate tectonic fissure zone formed a vertical crossflow recharge channel of the Cretaceous aquifer through the weakly permeable layer, which prompted the Cretaceous water to become an indirect recharge source of the mining area. The research results provide theoretical support for the prevention and control of water hazards and safe mining in similar mines in the western region.