Analytical Solutions for Thermomechanical Soil Structure Interaction in Single Energy Piles Exhibiting Irreversible Interface Behavior

The main purpose of this study was to derive analytical solutions for soil structure interaction in single energy piles that exhibit irreversible interface behavior. The solutions were derived for a pile embedded in a homogeneous soil layer subjected to thermal, mechanical, and thermomechanical loads. Furthermore, the solutions were subsequently validated against the experimental data obtained from the full-scale tests. Load transfer diagrams depicting evolutions of displacement, interface shear stress, and axial stress versus depth for semifloating, fully floating, and end-bearing piles were obtained from the analytical solutions and subsequently presented. The effects of a progression of thermally induced interface yielding on the displacement, interface shear stress, and axial stress were illustrated in case of heating and cooling for different end restraints. In addition, the analytical solutions show that the location of the null point changes after the initiation of the interface yielding. The analytical solutions indicate that residual displacement, strain, and stress are generated in the pile upon the initiation of the interface yielding. This finding was also confirmed through a comparison of analytical predictions with experimental data. Finally, analytical solutions show that evolutions of displacement, strain, and interface shear stress are hyperbolic trigonometric functions within the depth of the nonyielded interface. In contrast, within a depth corresponding to the yielded interface, axial stress and strain are linear functions, displacement is a quadratic function, while the interface shear stress is constant with depth.