中文摘要：

土壤水力参数是土壤水分运动和溶质迁移模拟计算的基本参数,因此快速、省时、精确的确定土壤水力参数有重要意义.本文建立了积水入渗条件下土壤水力参数优化模型,采用遗传算法与Levenberg-Marquardt算法相结合的混合遗传算法对其进行求解,并进行了数值实验和土柱实验验证.数值实验结果表明采用混合遗传算法求解积水入渗条件下的土壤水力参数具有较高的精度,参数优化精度与待优化参数的个数和积水入渗实验测定项目有关,当待求参数为rθ,,αn3个时,积水入渗实验中只需测定含水率和累积入渗量二者或二者中的任意一个均可求出参数值;当待求参数为rθ,sθ,,αn4个和rθ,sθ,,αn,Ks5个时,积水入渗实验需要测定含水率或同时测定含水率和累积入渗量方可求出待求参数,而仅测定累积入渗量不能精确求出rθ、sθ的值.应用上述分析结果,进行了土柱积水入渗实验,结果表明该模型可以精确求解土壤水力参数.因此,本文建立的土壤水力参数优化模型是正确的,求解方法是合理的,这可为高效求解土壤水力参数提供一个有效途径.

英文摘要：

The soil hydraulics parameters is the basic parameter of the soil water movement and the solute transport analog computation.Therefore,the fast,time-saving and precise determination soil hydraulics parameter has the important meaning.According to the ponding infiltration experiment,the optimized model of the soil hydraulic parameters was established,and the hybrid genetic algorithm which combines genetic algorithm with Levenberg-Marquardt optimization algorithm was used to solve it.A series of numerical experiments and soil column infiltration experiments were conducted to verify the model.The results showed that the optimized value with the hybrid genetic algorithm solving the soil hydraulics parameter optimizes model had higher precision.The optimized parameter precision is related to optimized parameter number and the number of test items in ponding infiltration.And when the optimized parameter is three（θr,α,n）,the ponding infiltration experiment measuring the moisture content,the accumulation infiltration or the moisture content and the accumulation infiltration all may accurately estimate the parameter value.When the optimized parameter is four（θr,θs,α,n）or five（θr,θs,α,n,Ks）,the ponding infiltration experiment measuring the moisture content or the moisture content and the accumulation infiltration may accurately estimate the parameter value but measuring the accumulation infiltration can not accurately estimate θr and θs value.Furthermore,the inverse method was verified by the ponding infiltration experiment in door.The results showed that the optimized model may solve accurately the soil hydraulic parameters.Therefore,this article establishing the soil hydraulics parameter optimization model is correct,and the solution method is reasonable.This provides a way for the highly effective solving the soil hydraulics parametes.