A simple method for numerical modelling of mechanical behaviour of an energy pile

A commercial numerical code was used to simulate the mechanical behaviour of energy piles under thermo-mechanical loadings. The thermal load was simply simulated by imposing on the pile volumetric strains calculated from the coefficient of thermal expansion of the material. Simulations were performed for two existing in situ experiments and one experiment performed using a physical laboratory model. Comparison between the simulations and experimental results shows that this decoupling method can satisfactorily predict the experimentally observed phenomena of pile head movement under thermal cycles at various mechanical loads and change of pile axial load along the pile under thermal cycles. The results highlight the important role played by thermal volume change of the pile on the mechanical behaviour of the energy pile under thermo-mechanical loadings.