Effect of Hydraulic Properties of Backfill and Geocomposite Drainage Materials on Seepage Response in Mechanically Stabilized Earth Walls

Abstract

This research aims to investigate the effect of water retention characteristic of the soil and drainage material (geocomposite) on seepage responses in mechanical stabilized earth walls by using geocomposite as drainage system. A set of experiments on physical models was conducted such that the data set obtained from the tests were used to calibrate the numerical models. The well calibrated numerical models were then used to perform parametric study. The studied parameters were van Genuchten parameters (ga, gn, Sres, Ssat) and coefficient of permeability (k) of the relevant materials. Results from the parametric study show that the water retention characteristic of the soil outside the reinforced zone plays no role to the hydraulic response of the soil inside the reinforced zone. However, the coefficient of permeability of the soil outside the reinforced zone plays important role to the level of the phreatic surface inside the reinforced zone. Hence, the coefficient of permeability of the soil outside the reinforced zone must be taken into account when designing drainage system.