ABSTRACT
This study investigated the characteristic length (D cha) as a parameter of the concept model for estimating unsaturated seepage behaviors. We aimed to improve the practicality of the model. The model was proposed by Sako and Kitamura (2006) to derive the seepage behavior of unsaturated soil. D cha is a parameter used to determine the pore size distribution in soil specimens. The methods for determining the parameters for each soil were discussed herein. In this study, a new parameter D rmv was proposed to determine D cha. The characteristics of this parameters were analyzed for volcanic sandy soil. The results indicated D rmv < 10 -3 mm for volcanic sandy soil and D rmv were related to the uniformity coefficient, U c. The validity of this method was verified by comparing the D rmv calculation with the experimental data for volcanic sandy soil sampled at a natural slope in Kagoshima Prefecture, Japan.
