一种基于VG模型的非饱和土渗流参数反演方法

针对非饱和土渗流分析中土水特征曲线和渗透性函数难以获取的问题,本文提出一种基于van Genuchten（VG）模型的非饱和土渗流参数反演方法,非饱和渗流控制方程采用Richards方程,通过计算数值模拟值与实测各观测点不同时刻孔隙水压力或重量（体积）含水量之误差平方和,寻求最优VG模型参数组合使得误差平方和最小.编制了二维非饱和渗流参数反演程序（BAKSEEP）,并通过算例展示了该程序良好的适用性和稳定性.

A Back Analysis Method for VG Model Parameters in Unsaturated Seepage Simulation

In unsaturated seepage numerical simulation, the soil-water characteristic curve and hydraulic conductivity function for unsaturated soils are difficult to be obtained. To solve this problem, a back analysis method for VG model parameters in unsaturated seepage simulation is presented. The Richards equation is used as governing equation for unsaturated seepage. The VG model is adopted for soil-water characteristic curve and hydraulic conductivity function. The summation of squared error between simulated pore water pressure or gravitational （volumetric） water content and measured value is calculated. A set of local optimized VG model parameters can be found with minimized the summation of squared errors. A two dimensional back analysis program for unsaturated seepage （BAKSEEP） is compiled. The results of a benchmark case show that the back analysis method for unsaturated seepage is robust and practical.