Effect of Thermal Cycles on the Uplift Capacity of Energy Piles using Physical Modeling

The use of shallow geothermal energy become a practical method for controlling building temperature. Structural elements such as piles, retaining walls, or tunnels can be adapted to act as ground heat exchangers while serving their primary load-bearing role. Since modern construction often requires deep foundations, combining structural and thermal functions in one system reduces overall costs and improves energy performance. Among these alternatives, energy piles have received particular attention. They not only contribute to soil-structure interaction but also supply renewable heat to buildings. Their efficiency is several times greater than that of common gas-based systems, which makes them attractive for long-term energy savings. Repeated heating and cooling, however, changes the temperature field around the pile and may influence its mechanical response. To study this effect, a set of ۱-g laboratory model tests was carried out. The experiments used a closed-end aluminum pile installed in Firoozkooh No. ۱۶۱ sand, with water circulating inside the pile to transfer heat. Thermal loading was applied through a water bath and a temperature regulator. Four tests were performed in total. The results showed a slight increase in uplift capacity under thermal cycling, but the change was very small and of little importance in design practice.

کلیدواژه ها:

Energy pile ، Renewable energy ، Physical modeling ، Uplift capacity