通过分析Green—Ampt模型和Philip模型计算累积入渗量的方程,利用两模型参数之间的转换关系,建立两个Green—Ampt模型累积入渗量的显函数,并对其适用性进行评价.不同土壤质地和田间试验条件下的入渗试验检验表明,显函数I计算的累积入渗量的IRE和RMSE分别为0.01%、0.34%、0.33%、0.33%、1.98%和0.13、0.05、0.09、0.09、0.09,显函数Ⅱ计算的累积入渗量的IRE和RMSE分别为1.53%、0.40%、2.11%、0.67%、4.88%和0.15、0.05、0.11、0.09、0.16,显函数Ⅰ和显函数Ⅱ的计算误差都较小,显函数Ⅰ的计算精度相对更高;土壤质地不同时显函数Ⅰ和显函数Ⅱ的计算精度都有较大差别;田间试验条件下显函数Ⅰ和显函数Ⅱ的计算精度都有所降低.此外建立的显函数结构较为简单,具有一定的物理基础,可利用建立的显函数解决入渗问题.
Through analyzing equations which were used to calculation cumulative infiltration in Green-Ampt model and Philip model, the paper established two explicit functions to cumulative infiltration of Green-Ampt model with the conversion relationship of parameters, and evaluated their applicability. The tests of ponded water infiltration experiment under different soil texture and field showed that when cumulative infiltration was calculated with explicit function Ⅰ , its integral relative error was 0. 01%, 0. 34%, 0. 33%, 0. 33%, 1.98%, and mot mean square error was 0. 13, 0. 05, 0.09, 0.09, 0. 09; when cumulative infiltration was calculated with explicit function Ⅱ, its integral relative error was 1.53%, 0. 40%, 2. 11%, 0. 67%, 4.88%, and root mean square error was 0. 15, 0. 05, 0. 11, 0. 09, 0. 16. The above results indicated that calculation error of explicit function Ⅰ and Ⅱ were less, but precision of explicit function Ⅰ was relatively higher; calculation error of explicit function Ⅰ and explicit function Ⅱ were different for different soil texture, precision of explicit function Ⅰ and Ⅱ in the field condition would decrease. Furthermore, established explicit functions had a simple structure and a certain physical foundation. These results presented above showed that explicit function Ⅰ and Ⅱ could be used to solve infiltration problems in the practical application.