A novel laboratory technique to determine the water retention curve of geosynthetic clay liners

Abstract

ABSTRACT: The aim of this paper is to discuss the suitability of different soil laboratory techniques for determining the water retention curve (WRC) of geosynthetic clay liners (GCLs), and to introduce a new testing method that takes into consideration the special geometric and structural configurations of GCLs. A modified triaxial apparatus was built for this purpose. The originality of this apparatus rests on a needle system attached to the conventional triaxial cap, which allows control of the moisture content of the tested specimen on the wetting path. Suction measurements were conducted using two different sensors: a thermocouple psychrometer and a relative humidity sensor. The applicability of the developed system was demonstrated by testing the GCL sample on the wetting path. The results obtained agree well with the data available in the literature. It is believed that the advantage of the developed testing system can be ascribed to its ability to control the moisture content on the wetting path and temperature of the tested specimen under triaxial stress conditions.