深埋煤层采动覆岩渗透能力变异与地下水响应模拟

针对西部深埋矿区煤炭资源开发对地下水扰动的相关研究不足的问题,依据弹塑性相关理论,利用多物理场数值模拟软件(COMSOL),研究了深埋煤层采动覆岩渗透能力变异与地下水的响应规律,模拟得出案例矿井在不同采动应力状态区覆岩渗透能力变化具有差异性:采动覆岩应力拉伸区岩体的渗透率相对增大,在采掘空间的直接顶渗透率增大26%,在地表沉陷盆地边缘增大3%;覆岩压缩区渗透率相对减小,在煤岩柱两侧渗透率减小43%,在采掘空间正上方约300m处渗透率减小18%。由于采掘后井下采掘空间直接与大气联通,形成了以导水裂缝带范围为中心的水压降落漏斗,导致垂向水力梯度与流速加剧;而在煤层顶板300m以上范围,水压水头基本为原始状态。研究成果为我国干旱与半干旱矿区煤-水资源合理开发、科学管控提供技术依据。

Study on permeability variation and groundwater response under disturbance of deep coal seam mining

There is a lack of research on groundwater disturbance caused by deep coal resource exploitation in western China. Based on the elastic-plastic theory , this paper studies the variation mechanism of the seepage capacity of the overlying strata and the response of the groundwater by using the fluid solid coupling numerical simulation software COMSOL. The simulation results showed that the change pattern of overburden permeability is different in different mining stress states. The overburden permeability increased in the tensile stress zone: at the top of the excavation space it increased by 26% , and in the surface subsidence basin it increased by 3% . The overburden permeability decreased in the stress compression zone: on both sides of the coal pillar it decreased by 43% , and at about 300m above the mining space it decreased by 18% . A groundwater drawdown funnel was formed with the water-flowing fractured zone as the center. As a result, the vertical hydraulic gradient and flow velocity of groundwater both increased significantly, while the water pressure was basically in the original state at about 300m above the mining space. The research results can provide theoretical support for reasonable exploitation of coal resources and scientific management of water resources in the arid area of China.