Effect of temperature on the shear strength of soils and the soil-structure interface

In the present work, the shear behaviour of soils and the soil-concrete interface is investigated through direct shear tests at various temperatures. A conventional direct shear apparatus, equipped with a temperature control system, was used to test sand, clay, and the clay-concrete interface at various temperatures (5, 20, and 40 °C). These values correspond to the range of temperatures observed near thermoactive geostructures. Tests were performed at normal stress values ranging from 5 to 80 kPa. Results show that the effect of temperature on the shear strength parameters of soils and the soil-concrete interface is negligible. A softening behaviour was observed during shearing of the clay-concrete interface, which was not the case with clay specimens. The peak strength of the clay-concrete interface is smaller than the ultimate shear strength of clay.