Thermal effects on behaviour of clay–structure interface under partial drainage

The shear behaviour of the soil–structure interface is crucial in determining shaft friction in energy geostructures and is influenced by complex thermo-mechanical loading paths. This study examines the effects of temperature (22°C and 60°C) on the shear response of a rough clay–structure interface under partially drained conditions, considering thermal loading duration and two normal boundary conditions: constant normal stress and constant normal stiffness (70 kPa/mm). Results show that peak shear stress increased with temperature, while residual shear stress remained largely unchanged. Thermal loading increased the interface friction angle, but its effect on adhesion depended on thermal loading duration. Adhesion increased with prior thermal consolidation but decreased when shearing occurred before complete consolidation. Thermal loading duration and the boundary condition influenced the displacement required to reach peak shear stress.