RE-EVALUATION OF HYDRAULIC CONDUCTIVITY ESTIMATION OF UNSATURATED SOILS WITH PARTICLE-SIZE DISTRIBUTION
MODELS

Hwang, Sang II

doi:2002.7.3.159

Environmental Engineering Research 2002;7(3): 159-167. DOI: https://doi.org/10.4491/eer.2002.7.3.159

RE-EVALUATION OF HYDRAULIC CONDUCTIVITY ESTIMATION OF UNSATURATED SOILS WITH PARTICLE-SIZE DISTRIBUTION MODELS

Sang II Hwang^†

Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Ave., Potsdam, NY 13699-5710, USA

Corresponding Author: Sang II Hwang ,Tel: +82-315-268-6495, Fax: +82-315-268-7985, Email: sangilh@clarkson.edu

Received: April 6, 2002; Accepted: August 6, 2002.

ABSTRACT

Knowledge on the unsaturated hydraulic conductivity function of soils is essential for many problems including water flow and solute transport in unsaturated soils. Recently, Arya et al. [12] developed a model to compute unsaturated hydraulic conductivity directly from particle-size distribution (PSD) of a soil. This model implies that details of a PSD curve may affect the estimation of unsaturated hydraulic conductivity. To determine whether the unsaturated hydraulic conductivity estimation using the Arya et al. model could be affected by the selection of a PSD model, four PSD models with one to four fitting parameters were used. The Jaky model with only one fitting parameter showed better performance for estimating the unsaturated hydraulic conductivity than other models with more fitting parameters. It indicates that both inherent measurement errors in the soil database used in this study and difference between gross textural characteristics and hydrophysical behavior of individual soils could eliminate the effect of more detailed and accurate PSD representation obtained with models with more fitting parameters.

Keywords: Arya et al. model | Jaky model | particle-size distribution | unsaturated hydraulic conductivity | unsaturated soil