Soil–pile thermal interactions in energy foundations

In this technical note, the results of a set of simplified numerical analyses are presented. The analyses were undertaken in order to examine the validity of a descriptive framework that was previously proposed to illustrate the behaviour of thermally activated piles and to highlight the potential limitations of some analytical methods that are being applied to their study and design. Working on the premise that some soils, specifically moderately to highly over-consolidated clays, may experience thermally induced volume changes larger than concrete elements inserted into the ground, the results of the study highlight that analyses that do not account for the initial temperature field and boundary conditions, and the response of the ground to temperature changes, may yield erroneous conclusions with respect to the performance of operational thermally activated piles used to support temperature-controlled structures.