Temperature-controlled interface shear testing of geosynthetics: an experimental study

Although geosynthetics can be exposed to relatively different temperatures during their lifetime, testing of their interfaces is typically conducted at a range of 20°C–27°C, as recommended by various standards. In the present study a novel temperature-controlled interface shear apparatus has been developed, that uses a two-tier heating system to ensure efficient and uniform heating while minimizing heat loss. Three different interfaces, namely soil-geomembrane (GMB), geotextile (GTX)-GMB, and soil-soil, have been investigated at four different ambient temperatures. The results reveal strain softening behavior in the interfaces that contain at least one geosynthetic material. For normal stress of 100 kPa, the reduction in shear strength after reaching peak ranged from 11% to 23% for soil-GMB and 24% to 34% for GTX-GMB as temperature varied from 25°C to 80°C. In contrast soil-soil interface indicated insensitivity to temperature variations with marginal variations. A pilot scale study has been conducted to evaluate the sensitivity of temperature on the overall stability of the slope. These findings confirmed the detrimental effects of elevated temperature on the factor of safety of the lined slopes. The study highlights the importance of considering in situ temperature conditions during design of liners for better performance of structure.