考虑地下水入渗的一维水动力学模型研究

Study on one-dimensional hydrodynamic model-building considering groundwater infiltration

考虑地下水入渗的一维水动力学模型可从物理机制上综合模拟河道水流与地下水之间的互动关系,为地下水入渗过程活跃河段的水流模拟提供基础方法。引入达西定律,通过渗流方向假设及渗流路径长度假设,推导构建了地下水入渗项的数学表达式。分析表明,该项可合理反映河道水流与地下水间的补给与反补给关系;将其整合至圣维南方程组,并通过Preissmann四点线性隐式差分格式求解。从理论上讨论了该模型的适用条件。当地下水入渗没有严格符合假设条件时,可通过调整渗透系数及平均导渗率弥补。考虑地下水入渗的一维水动力学模型能够动态反映河道上各断面水流与地下水之间的交互关系,定量分析地下水入渗水量,有利于提高一维水流的模拟精度。

The one-dimensional hydrodynamic model considering groundwater infiltration can simulate the interaction between river flow and groundwater in the aspect of physical mechanism, which provides a basic method of simulating the flow in the active reach of river during groundwater-infiltration. By introducing Darcy’s law, the mathematical expression of groundwater infiltration is deduced and established through assuming both the percolation direction and the length of percolation path. Analysis shows that this item can reasonably reflect the relationship of charge and recharge between river flow and groundwater, which is integrated into Saint Venant equations and then is solved through the four point linear implicit difference scheme, while the applicable conditions of the model are theoretically discussed as well. When groundwater infiltration is not strictly consistent with the relevant assumed conditions, it can be made up by adjusting the permeability coefficient and the average infiltration rate. The one-dimensional hydrodynamic model considering groundwater infiltration can dynamically reflect the interaction between water flow and groundwater in all the sections of river channel and quantitatively analyze groundwater infiltration volume, thus it is favorable to enhance the accuracy of one-dimensional flow simulation concerned.