The modified van Genuchten-Mualem model on Hydraulic Conductivity to improve reliability and numerical stability near saturation

Abstract

Hydraulic Conductivity (HC) is integrated theoretically using Soil Water Retention Curves (SWRC) by Mualem capillary model, but extremely sensitive to small variation of SWRC near saturation. The van Genuchten SWRC model is modified within range for low matric suction range on a linearized log scale to improve the Van Genuchten-Mualem (VGM) model for predicting the HC. Using the modified SWRC, the VGM HC can be improved by integrating for each decomposed interval and analytical solutions are proposed. The conductivities in experiments are compared with the HC models deduced from the SWRCs. The saturated HC is conserved by the modified VGM model, which improves numerical stability near saturation. The modified VGM model predicts more accurate HC functions by correction of pore connectivity factor for Korean residual soils.