Comparison between Campbell and van Genuchten models by inverse estimation of unsaturated properties.

Abstract

Inverse technique to evaluate the unsaturated hydraulic properties of soil/rock was studied using Campbell and van Genuchten models, as the functions of the hydraulic properties. When the parameters of these models are given, the evaporation change under the constant climate and the simple boundary conditions can be calculated with considering the liquid and vapor flows in soil/rock. So that, the parameters can be inversely estimated by fitting the calculated evaporation change to the measured one. Genetic Algorithm (GA) was adapted to find the best parameters in these two models. It was found that the parameters in those models could be well estimated by this technique and the transient evaporation change and the moisture profile in homogeneous soil could be well simulated.