Temperature-Dependent Shear Behavior of Geosynthetic Clay Liners

The use of geosynthetic clay liners (GCLs) in barrier systems for waste containment can expose GCLs to different internal stress conditions and elevated temperatures. Thus, evaluation of the internal shear strength of GCLs as a function of normal stress and temperature is important to the design and integrity of barrier systems. In this study, internal shear strength of GCLs was evaluated in stress-controlled shear tests at a range of temperatures from 20 degrees C to 80 degrees C and under 20, 40, and 60 kPa normal stress. Horizontal shear deformation increased with increasing temperature, but decreased with increasing normal stress. Increased deformation with increasing temperature was attributed to reduced tensile strength of the needle-punched reinforcement fibers. The ratio of shear-to-normal stress at failure decreased from approximately 1.5 to 1.2 with an increase in temperature from 20 degrees C to 80 degrees C, and was independent of normal stress.