基于Green-Ampt和Philip模型的波涌灌间歇入渗模型研究

Intermittent Infiltration of Surge Irrigation Model Research Based on Green-Ampt and Philip Models

摘要:

为了进一步揭示波涌灌间歇入渗的影响机制与规律，基于Green-Ampt和Philip入渗模型理论，建立了波涌灌间歇入渗分区模型，将第2供水周期及其后的供水周期内形成的入渗湿润区分别划分为重力势湿润区和基质势湿润区，并阐述了基于间歇入渗过程湿润区的分区入渗理论，通过Green-Ampt模型和Philip模型参数间的内在联系，建立了关于土壤体积含水率增量与累积入渗量之间的数学模型，并进一步根据土壤体积含水率增量与累积入渗量之间的线性图形特征，确定了不同分区下各供水周期的水分运动参数,分别为湿润锋面处吸力hf与表征饱和导水率Ks，且各间歇周期供水阶段的hf随着周期数的增大呈减小趋势，最后，利用分区模型将不同供水周期下的累积入渗量与湿润锋运移距离计算值同实测资料相比较，与实际值相比总体平均相对偏差分别为3.6%和8.6%，改进模型的适用性较好，拟合精度较高。因此，该模型可以较准确地描述波涌灌间歇入渗机理，为波涌灌灌水技术的合理设计提供了理论依据。

Abstract:

In order to reveal the further influence mechanism and law of intermittent infiltration of surge irrigation,based on the theory of Green-Ampt and Philip models, this paper proposes the concept of dividing the infiltration and wetting zone of the second water supply period and later period of water supply into two zones. The two zones were humid region of gravity potential and matrix potential. And the infiltration of concept characteristics of two zones was described. Building a mathematical model of the increasing capacity of volumetric water content by the inner relationship between the parameters of the two models (Green-Ampt and Philip models) and based on the linear pattern characteristics between the increment of soil volumetric water content and cumulative infiltration capacity, the water movement parameters of different water supply periods were determined. One of the water movement parameters was suction value of wetting flog hf and another was characterized saturated hydraulic conductivity Ks. The value of hf of intermittent period has the decreasing trend with the increase of the number of cycles. Finally, using the improved model to compare the calculated cumulative infiltration capacity and wetting front with measured data, a higher fitting precision was acquired. Compared with the measured data, the overall average relative deviations were 3.6% and 8.6% respectively. The improved model has good applicability. Hence a more accurate description of the mechanism of intermittent infiltration of surge irrigation could be described by this model which provides theoretical basis for the reasonable design of surge flow irrigation technology.