Issues Involved With Thermoactive Geotechnical Systems: Characterization of Thermomechanical Soil Behavior and Soil-Structure Interface Behavior-Article

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The paper reviews how thermohydromechanical soil behavior and soil–structure interaction affect thermoactive geotechnical systems, such as energy foundations. It concludes that behavior of saturated soils is relatively well understood and can be modeled with established constitutive frameworks, but important research and engineering challenges remain.<br /><br />For saturated clays, heating generally causes normally consolidated soils to contract and highly overconsolidated soils to expand; the response depends on soil type, plasticity, stress history, and temperature. Heating can also reduce preconsolidation pressure. The influence of temperature on shear strength is inconsistent across studies, reflecting differences in materials, drainage, and thermal and mechanical histories.<br /><br />Understanding unsaturated soils is less developed. Temperature can alter suction, saturation, volume change, and strength, with outcomes depending on stress state and the sequence of heating and drying. Anisotropic stresses and repeated heating–cooling cycles also require more investigation, including possible cumulative deformation and long-term effects.<br /><br />Reliable laboratory characterization requires specialized temperature-controlled equipment, careful calibration and insulation, controlled boundary conditions, and attention to thermal gradients and cyclic loading. Because testing methods vary, standardization and wider availability of suitable equipment are needed.<br /><br />Soil–concrete interface behavior is another major uncertainty. Experiments report differing temperature effects on interface strength, and the mechanisms may include thermal expansion, drying, and restraint of soil dilation. Further work should clarify these processes, as well as heat-related water flow and the extent of the affected soil zone.<br /><br />Overall, the paper identifies unsaturated conditions, anisotropy, cyclic thermal loading, temperature-dependent preconsolidation stress, and interface behavior as priorities for improving models and predicting thermoactive foundation performance.

Keywords

thermohydromechanical behavior

soil-structure interaction

thermoactive geotechnical systems

energy foundations

saturated clays

unsaturated soils

temperature effects

shear strength

soil-concrete interface

cyclic thermal loading