Use of Inverse Problem Theory to Estimate Hydraulic Conductivity Parameters of Unsaturated Soil by the Infiltration Tests

摘要

Many types of apparatus and procedures were developed to measure the soil permeability in situ. The used assumptions generally hold for saturated soils. Test resutls do not take into account the saturation process. Solving hydrodynamic equations in porous media for suitable conductivity and diffusivity laws, water profiles were calculated. From these profiles, cumulative infiltration was computed. Using inverse problem method, values of hydraulic conductivity and diffusivity were changed until calculated infiltration curve fits experimental infiltration curve. Rosenbrock method gives the optimal values of soil hydrody-namic parameters. Water profiles were calculated with these parameters. Several numerical tests proved that is necessary to solve simultaneous the equation with a volumetric water content variable and effective pressure variable to get good fitting between experimental water profiles and calculated water profiles.