Issues involved with thermoactive geotechnical systems: characterization of thermomechanical soil behavior and soil-structure interface behavior

Abstract This paper focuses on the main issues discussed during a session on the impact of thermohydromechanical behavior of soils on thermoactive geotechnical systems, and how they could affect the performance of thermoactive geotechnical systems. Both soil behavior as well as soil–structure interaction behavior was discussed. The main observation from the session was that the thermohydromechanical behavior of saturated soils has reached a mature understanding, with several established constitutive models that can be used by engineers. However, there are still opportunities to enhance these constitutive models by considering issues such as unsaturated conditions, anisotropic stress states, cyclic heating and cooling effects, and changes in the preconsolidation stress during heating and cooling. Further there are still opportunities to improve our understanding of soil/concrete interface behavior, including the development of novel testing approaches.