Thermo-mechanical behavior of a full-scale energy pile equipped with a spiral pipe configuration

This study investigates the thermo-mechanical behavior of energy piles equipped with a spiral pipe configuration. The analysis is based on the results of a full-scale energy pile as well as 3-D thermo-mechanical finite element analyses. The thermo-mechanical behavior of two energy piles with five U-shaped pipes connected in series and parallel, characterized by the same total length of the piping network, is also analyzed numerically for comparison purposes. The results of this work highlight that energy piles equipped with a spiral pipe configuration are characterized by the lowest trends of average temperature variation and thermally induced vertical stress within their volume, as compared to energy piles equipped with five U-shaped pipe configurations connected in series or parallel. Considerable variations in temperature and thermally induced vertical stress arise in the vicinity of the piping network embedded in all of the considered energy piles. Nevertheless, energy piles equipped with a spiral pipe configuration appear the best solution for practical applications in comparison with U-shaped pipe configurations of the same total length, because they maximize the heat exchange that is achieved with the ground and minimize the associated thermally induced variations of their mechanical response.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author