Design charts for geothermal piles under various thermo‐mechanical conditions

Abstract

AbstractAmong new “green technologies” in geotechnical engineering, geothermal piles appear to be an economical and cost‐friendly solution to combine shallow geothermal energy to the primary function of piles. Nevertheless, in comparison to conventional piles, they are subjected both to thermal and mechanical loadings, which arise some questioning regarding their behaviour and their mechanical design. Efficient and unambiguous calculation procedures are required in order to provide appropriate and progressive verification levels. In order to provide a first view of the design of energy piles, the main objective of this paper is to propose design diagrams that account for: i) rigidity of the overburden structure, ii) consequences of ground thermo‐volumetric strains, their link with the characteristics of the thermal loading and subsequent transient phenomena and iii) cyclic issues. This article presents a synthesis of the improvement related to these issues. Simplified design charts including these different aspects are finally proposed.