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采动条件下含水层渗透性演化特征及动态涌水量预计

Evolution of aquifer permeability under mining conditions and prediction of dynamic water inflow

  • 摘要: 招贤煤矿是黄陇煤炭基地的重要矿区,高强度煤矿资源开采过程中煤层顶板水害问题突出,涌水量预测是矿区水害防控的重要一环。煤层开采破坏了上覆岩层原有的应力平衡状态,是含水层渗透性变化的关键诱因,为探究采动条件下含水层渗透性演化特征及涌水量的动态预计,基于矿区开展的群孔抽水试验,采用数值模拟、数理统计等方法,分析煤矿开采不同时期含水层渗透系数及地下水流场的变化特征,建立研究区数值模型进行动态涌水量预计。结果显示:煤层开采过程中,含水层渗透系数呈现先增大后减小的变化特征,开采活动停止后渗透系数的增长仍会持续一段时间,开采过程中含水层渗透系数变化范围为4.3~22.0倍。含水层渗透性的改变影响了地下水流场的分布,渗透性强的区域地下水水位更加均一;受采动影响的含水层中,地下水的活跃性增强,地下水水位的恢复速度更快。结合开采过程中含水层渗透性变化特征,并通过涌水量分段模拟的方法,对预开采工作面涌水量进行了预测。研究成果可为矿井开采过程中含水层渗透性演化特征的认识提供参考,为矿井水害防治及安全生产提供依据。

     

    Abstract: Zhaoxian mining area is an important mining area in the Huanglong coal base. During the mining of high-strength coal resources, the problem of coal seam roof water disaster is prominent, and water inflow prediction is a crucial part of water disaster prevention and control in the mining area. Coal seam mining disrupts the original stress equilibrium state of the overlying strata and is a key factor inducing changes in aquifer permeability. To explore the evolution characteristics of aquifer permeability and the dynamic prediction of water inflow under mining conditions, multiple-group pumping tests conducted in the mining area are used as the basis, and research methods such as numerical simulation and mathematical statistics are comprehensively applied to analyze the variation characteristics of the aquifer permeability coefficient and groundwater flow field at different stages of coal mining. A numerical model of the study area is established to dynamically predict water inflow. The results indicate that during coal seam mining, the permeability coefficient of the aquifer first increases and then decreases. After mining activities cease, the increase in the permeability coefficient continues for a period of time, The variation range of the aquifer permeability coefficient during the mining process is 4.3 to 22.0 times. Changes in aquifer permeability affect the distribution of the groundwater flow field, and groundwater levels are more uniform in areas with higher permeability. In aquifers affected by mining activities, groundwater activity increases, and the groundwater level recovers more rapidly. By combining the variation characteristics of aquifer permeability during the mining process and adopting a segmented simulation method for water inflow, the water inflow of the pre-mining working face is predicted. The research results can provide a reference for understanding the evolution characteristics of aquifer permeability during mine exploitation and provide a basis for mine water disaster prevention and control and safe production.

     

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