Thermomechanical analysis of dissimilar energy pile groups using a load transfer method

Engineering practice has shown that dissimilar pile groups, consisting of piles with varying diameters or lengths, are more effective in mitigating differential settlement compared to homogeneous configurations. However, the thermomechanical behavior of dissimilar pile groups remains poorly understood, primarily due to the complex interplay of pile‒pile interactions and thermal operations. Existing analytical methods for energy pile groups mainly focus on homogeneous piles, presenting a critical research gap. This study introduces a load transfer method to analyze the thermomechanical performance of the dissimilar energy pile group. The proposed method derives expressions for interaction parameters that characterize the sheltering‒reinforcing effect between dissimilar piles based on the elastic theory, considering pile‒soil, pile‒slab, and pile‒pile interactions. The proposed method is validated against experimental data and finite-element simulations, showing strong agreement with prediction errors consistently within 5 %. Additionally, the effects of pile length, diameter, and spacing on the behavior of the dissimilar energy pile group are examined using a basic two-pile unit. The results demonstrate that the proposed method effectively captures key metrics, such as axial stress distribution and displacement profiles, providing an accurate assessment of dissimilar energy pile group behavior.