Understanding the temperature-induced mechanical behaviour of energy pile foundations

This paper discusses physical process of thermal transfer in energy pile foundations, which function as structural support for the buildings as well as heat exchangers serving energy to the buildings. Derivation of conservation of energy balance is presented, depends on its type of heat transfer within a whole system of soil and foundation. In order to understand the mechanical implication behind their application, simulation numeric with finite difference method is conducted, concerning an energy pile in homogenous soil under static thermal load. The study takes into account two different conditions of contact between soil and pile: perfectly contact and sliding contact using frictional interface elements. The results show that temperature-induced mechanical behaviour of pile and soil is strongly related to the condition of contact between them. Further work is projected to consider a more appropriate law that corresponds to cyclic thermal loading of energy piles due to its seasonal cooling and heating operation throughout the year. (C) 2012 Elsevier Ltd. All rights reserved.