Review of the Characterization of Geotextile Hydraulic Behavior

Geotextiles have been widely used in soil structures such as road, embankment and reservoir as a drainage material. The aim of this paper is to give a comprehensive review of the characterization of geotextile hydraulic behavior in the past and present. The review includes the wetting and wicking theories, the hydraulic behavior characterization techniques, and the application of unsaturated soil mechanics in geotextile hydraulic behavior. Wetting and wicking are two coupled phenomena that drive the liquid to flow in geotextiles. Capillary pressure and permeability are two major parameters to characterize geotextile hydraulic behavior. The upward-horizontal-downward (UHD) characterization method can be used to quantify those parameters. However, the geotextile may not drain the water as originally expected under unsaturated conditions. Unsaturated soil theory provides as an effective tool to explain and evaluate the hydraulic behavior of geotextile in unsaturated condition. Unsaturated geotextiles not only can serve as drainage material (within transient stage), but also as capillary barrier (within boundary effect and residual stages).