单坑变水头入渗条件下均质土壤水分运动的数值模拟

变水头入渗条件下的土壤水分运动是蓄水坑灌的基本理论问题。该文根据土壤水动力学的基本理论，分析了蓄水坑变水头入渗的复杂边界条件，并推导了其坑水位变化与坑壁变水头入渗关系的数学表达式，进而建立了蓄水坑灌单坑变水头入渗及土壤水分运动的数学模型。采用ADI交替方向隐式差分格式将土壤水分运动方程离散，用Gauess-Seidel迭代算法求解非线性差分方程，实现了单坑变水头条件下的土壤水分运动的数值模拟。实验验证表明，数值计算结果与实测值有着较好的一致性。

Numerical simulation of homogenous soil moisture movement under varying-head infiltration of single water storage pit

Soil moisture movement under varying-head infiltration is a basic theoretical problem of water storage pit irrigation. According to the fundamental theory of soil moisture dynamics, the complicated varying-head infiltration boundary of water storage pit irrigation was analyzed, the mathematic expression between water level and varying-head infiltration of pit wall was obtained, and the numerical model of soil water movement was established under the condition of water storage pit irrigation. ADI method and Gauess-Seidel iterative method were used to realize the numerical simulation of soil moisture movement under varying-head infiltration of single water storage pit. A series of experiments were conducted to verify the model. The results indicate that the calculated results are in accordance with the experimental results.