Study on dynamic method of calculating irrigation infiltration intensity based on unconfined groundwater table
In irrigation areas where both ditch lateral infiltration and field infiltration are not negligible,it is difficult to calculate field infiltration and ditch lateral infiltration on the basis of the dynamic data of unconfined groundwater table.According to the basic principle of groundwater dynamics,when the field infiltration intensity e is a constant,e is used as the source and sink term,the basic model of unsteady seepage of phreatic water near the ditch is constructed.The model was linearized and homogenized,and the model solution was obtained by Laplace transform.For the infiltration intensity varying with time,using the segmented function,e(t)is discretized,and the model solution is obtained according to the superposition principle.By using the model solution,a recursive formula for retrieving the field infiltration intensity using the dynamic data of unconfined groundwater table is established.Combined with Darcy's law,the formula for retrieving the lateral infiltration of ditches is given,and the influence of ditch boundary on the variation of unconfined groundwater table and the lateral infiltration intensity is discussed.The above calculation process is demonstrated by taking the dynamics of unconfined groundwater table near a trunk canal in the North Huaibei Plain as an example;the contribution of ditch lateral seepage to the change of submersible water level increases rapidly from 4.3％at the beginning to 62.8％at the end of the 48-h calculation period.The proposed dynamic method for calculating irrigation infiltration intensity can provide reference for the calculation of irrigation water infiltration into groundwater.
lateral seepage in ditchesfield infiltrationphreatic unsteady flowlinearizationhomogenization
万方数据
维普
