Study on thermo-mechanical properties of energy piles based on the improved exponential model

Abstract

To further investigate the effects of temperature on the bearing capacity of the energy pile, the influence of soil temperature was considered and the pile top displacement corresponding to the ultimate side friction resistance of the energy pile was obtained. An improved exponential model that accounts for the influence of pile-soil temperature was developed. The feasibility of the model was verified through an indoor model test and numerical simulation. The results indicate that the error between the improved exponential model and the indoor model test was smaller compared with the numerical simulation. The maximum side friction error between the improved exponential model and the model test reached 0.8 % and 4.6 % at the end of the heating and cooling stages, respectively. The maximum additional thermal stress error between the improved model and the model test was 1.3% and 3.9% at the end of the heating and cooling stages, respectively. The error of the traditional and improved exponential model of additional thermal stress was 16 %. It is established that the improved exponential model was proved suitable for thermo-mechanical coupling analysis of energy piles. The temperature effect of the soil should be considered in the investigation of the energy pile.