Modification of Green-Ampt model based on the stratification hypothesis
摘要
A modification of Green-Ampt model is proposed based on the stratification hypothesis,which dynamically divided the soil column is into saturated layer,transient layer and dry layer.The model uses the concept of an equivalent hydraulic conductivity in the saturated layer,and employs a new method to estimate the Green Ampt wetting front suction.The Richards equation is used to simulate the soil water movement through all three layers,and to study the properties of soil layers including the thickness,the soil water content,and the hydraulic conductivity.The results show that the ratio of the transient layer to the saturated layer decreases linearly as the soil profile becomes wetter.Moreover,the ponding depth and the profile of initial soil water content influence the interception and the slope of the linear relationship.However,the saturated hydraulic conductivity is found to have no measureable influence on the relationship.The soil water content in the transition layer follows an elliptical distribution,and the hydraulic conductivity decreases linearly with the increase of the soil depth in the layer.The infiltration process can be better simulated by the modified Green-Ampt model.