通量上边界渗透系数随埋深增加指数衰减的地下水流系统

Effect of Decay Exponential in Hydraulic Conductivity with Depth on Groundwater Flow System Based on Flux Upper Boundary

地下水流系统理论是当代水文地质学的核心概念框架,研究不同控制因素对盆地地下水流系统发育模式的影响具有重要意义。近年来的研究表明利用通量上边界能够更好地揭示盆地不同要素对地下水流系统模式转化的影响。基于通量上边界,采用数值模拟方法,研究稳定流条件下,渗透系数随埋深呈指数衰减的非均质含水层对盆地地下水流系统模式转化的影响。结果表明:随着渗透系数随埋深指数衰减程度的加大,盆地潜水面整体抬升,盆地上部地下水流速增大,水力梯度增大;同时,盆地地下水流系统由复杂的多级次水流系统到单一的局部水流系统,顺向局部水流系统占据的空间消减,而逆向局部水流系统占据的空间增大,流速近似为零的局部滞留区域向左下方移动。

The theory of groundwater flow system ts ttae core conceptual geology. It is very important to study the influence of different control factors to the groundwater flow system development pattern. Researches of recent years have put forward that flux upper boundary can better reveal the influence of different factors to the change of the groundwater flow system pattern. We simulate basin groundwater flow system based on flux upper boundary and study the influence of decayed hydraulic conductivity with depth to the change of groundwater flow system pattern when the flow is steady. Studies show that with the attenuation speed of hydraulic conductivity increasing, the water level raises and the velocities of the upper basin increase, and the hydraulic gradient increases. Meanwhile, the groundwater flow system is varied from complex multi-order flow system to a local flow system. The spaces of antegrade local flow systems become smaller and that of reverse local flow systems become big- ger. The circular areas whose velocity is approximate to zero move to the lower left corner.