UC San Diego

This paper focuses on the evaluation of the thermo-mechanical response of a 15.2 m-long energy foundation in dry sandstone over a 4-month period. Although the foundation was not actively heated or cooled using a heat pump, the fluctuations in the temperature of the heat exchange fluid occurred due to seasonal variations in the mechanical room temperature. Although these fluctuations only led to small changes in foundation temperature (from -1 to 1°C), these were sufficient to evaluate the mobilized coefficient of thermal expansion of the foundation. Further, the trends in the thermal axial stress and strain with depth in the foundation were evaluated, along with the mobilized side shear stress and axial displacement.