黄土中Green-Ampt入渗模型的改进与验证

Improvement and evaluation of the Green-Ampt model in loess soil

本文根据黄土积水入渗的土壤水分剖面变化特征,仅将饱和层与传导层统一视为饱和区,而将非饱和湿润层的含水量变化视为施加于饱和区的吸力势,从而在具有"活塞模型"之称的Green Ampt入渗模型基础上,推导得出了适用于黄土区的积水入渗模型。该模型不仅可计算累积入渗量及湿润锋深度,而且还可估算出土壤水分剖面分布状况。经甘肃秦王川地区实测资料的检验,表明模型具有较好的吻合性。

According to the characteristics of the water profile of ponding infiltration in loess soil,the authors proposed an improved GreenAmpt model,in which the original saturated zone and transient region were combined into a single saturated region,while the gradient of water content in the unsaturated zone was treated as the gradient of soil suction exerting over the upper surface of the saturated region.In contrast to the original GreenAmpt model that was only useful for calculating the accumulated infiltration rate,the improved model can also be used to calculate the wetting front and the water content profile.The model was verified with an experiment of the Qinwangchuan region in Gansu Province and the result showed a good agreement between the model prediction and observed data.