Abstract: The soil-pile interaction has always been of critical importance in geotechnical engineering related to pile foundations. However, there’s a lack of research and insufficient understanding regarding the load bearing performance for energy piles due to the unusual loading conditions where both the thermal and mechanical loading apply. Based on the ideal elastoplastic model and the hyperbolic model, a new pile-soil load transfer model considering Masing’s rule was proposed. The proposed model adopted the piecewise nonlinear method to modify the pile-soil load transfer backbone curve. Extensive numerical investigations were conducted to investigate the impact of the loading on the thermo-mechanical behavior of the energy piles. In addition, a physical model test was conducted to provide an in-depth understanding of the load transfer mechanism between the soil and the energy pile, and the thermo-mechanical behavior of energy piles. The axial stress and shaft resistance were measured as the temperature and depth changed. The results compared with those from the improved-approach-based numerical calculations indicate that thermo-mechanical behavior of energy piles can be described by the modified pile-soil load transfer model. The results obtained by the numerical simulation are in alignment with that of the physical model test, indicating that the modified model is suitable for the energy piles considering both the mechanical and cyclic thermal loading.

Key words: energy pile, soil-pile interaction, load transfer, numerical investigation, physical model test