探讨考虑气阻作用下分层假定的雨水入渗计算分析模型

Analysis model for rainwater infiltration considering gas resistance under stratified assumption

入渗时间和湿润锋深度关系可依据达西定律和入渗雨水质量守恒即入渗率等于入渗量对时间的导数求解,但Green-Ampt入渗模型以湿润区完全饱和考虑入渗量,同时入渗率也忽略了气阻作用,继而限制了入渗时间和湿润锋深度关系的计算精度。针对这一问题,通过分层假定和增加气阻项的入渗模型分别对入渗量和入渗率进行修正,并应用修正结果计算入渗时间和湿润锋深度的表达式。研究表明:同一入渗深度,考虑气阻项的分层假设模型的入渗时间计算值与实测值吻合度最高,偏离度很低,仅仅围绕实测值有很微小的上下波动,此研究结果对确定如含砂层稳定入渗时间具有重要作用。

The relation between infiltration time and wetting front depth is solved by the Darcy＇s law and the conservation of mass which is equal to the time derivative of cumulative infiltration, but both cumulative infiltration of completely saturated wet area and the infiltration rate derived from Green-Ampt model which ignores air resistance effect limit the calculation accuracy between infiltration time and wetting front depth. In order to solve this problem, the model is modified through stratified assumption and adding air resistance. The corrected results are used to solve the relationship between the infiltration time and the wetting front depth. The results show that at the same infiltration depth, the calculated infiltration time considering gas resistance term in the stratified hypothesis model agrees with the measured value. And the deviation degree is very low, and there is only a very small fluctuation. The test results play an important role in confirming the infiltration time of stable infiltration of sand layers.