Evaluating the methods for predicting permeability of unsaturated soils

Abstract

The unsaturated permeability (kuns) is one of the key parameters in geotechnical and geo-environmental engineering involving unsaturated soils. To measured kuns in a matrix suction range of few Pa to thousands of kPa is time consuming and sometimes not practical. Thus, various methods for predicting the values of kuns were established, and their performances are quite different. The performance of two commonly used methods, i.e. Mualem’s method adopting Van Genuchten’s soil water characteristic curve (SWCC) (designated as MVG), and Fredlund et al.’s method (designated as FXM), have been evaluated comparing the predicted values with the measured data, which are test data from this study and the data from literature. The analysis results indicate that MVG method yielded a better prediction.