蒸发条件下地下水对1m土体水分补给的数值模拟

Recharge of Ground Water to Soil 1m below the Surface──Numerical Simulation and Analysis of Soil Water Flux

采用数值方法，模拟分析了6种典型土壤的1m主体在不同蒸发强度条件下地表下20，50，100cm处土壤水分通量与地下水理深之间的关系。研究结果表明：若以5d或10d为平均时段，在一定的地下水理深条件下，土壤剖面中各深度的水分通量与土壤质地及水面蒸发强度间的关系可用土壤水分包络线图来表示。应用该包络线图，可分析计算裸地不同地下水埋深、不同蒸发条件下地下水对1m主体的补给量。在同样的水面蒸发强度下，地下水埋深起大，则谷深度的水分通量越小，当地下水理深大于3m时，地下水对1m主体已基本没有补给。

?In the present study, soil water flux of 20, 50 and 100 cm below the soil surface,under the conditions of different evaporation rate, groundwater table and soil texture, wascalculated by Galerkin Finite Element Method. The average time step of the relative flux wasselected as 5 d and 10 d so as to coincide with the water balance method. The simulationresults demonstrated the following: with a definite groundwater table, the relationshipbetween the soil water flux at different depth and Ks/Eo(Ks: the saturated hydraulic conduc-tivity4 E,: the evaporation rate from the free water surface) could be described with the SoilWater Flux Changing-Range Chart, on which there were only two series lines, the first wasset for the maximum mean flux at a certain depth, the second for the minimum. Based on theChart, the recharge of groundwater to soil lm below the surface can be calculated easi1y.