Pile Group Response to Thermal Cycles and Associated Alterations in Soil Response

In this study, the thermomechanical response of the pile group and associated impacts on surrounding soil are explored numerically for different (1) layouts of energy and conventional piles, (2) soil types, and (3) pile spacing for the pile groups in Ottawa sand and Toyoura sand. The study outcomes demonstrate cyclic alterations in load-displacement characteristics of the piles and the soil during cyclic thermal loading and unloading of energy piles. Conventional piles exhibit uplift when energy piles are thermally loaded, with notable differential pile base displacement. Higher pile spacing results in decreased thermomechanical stresses in the piles. Compared with the middle energy pile in the same row, the corner energy pile experiences significant axial stresses. The radial stresses in the soil at the pile-soil contact increase due to the cyclic thermal expansion of energy piles. In addition, the layout of energy piles, pile location, soil type, and pile spacing control the load-transfer response of pile groups.