Water retention behaviour of unsaturated geosynthetic clay liners

Geosynthetic clay liners (GCLs) have increasing importance in the geoenvironmental fi eld for use as hydraulic/gas barriers in waste containment applications. One important characteristic of GCLs in these applications is their water retention curve (WRC). Obtaining the WRC of a GCL is a challenging task due to its composite structure and the very large suction range associated with the bentonite component. Previous studies have examined the water retention characteristics of the individual GCL components namely: geotextile and bentonite, as well as the composite GCL using a variety of techniques to deal with the very wide range of suctions. This paper investigates the water retention of the composite structure of GCL using both contact and non-contact fi lter paper tests. This paper presents experimental results for a particular GCL as well their analysis using calibration equations derived by Leong et al. (2002).