A novel theoretical model of heterogeneous soil-pile interaction for investigating the torsionally loaded pile

Abstract

Abstract A new theoretical model of heterogeneous soil-pile interaction (HSPI) in torsion is developed in this study to analyze the behavior of an end-bearing pile under torque. By assuming the surrounding soil as an elastic continuum following a power law variation in shear modulus depth, new governing equations are established for the torsional deformation of the continuous heterogeneous soil and pile system subjected to torque. Separation of variables and principles of Sturm-Liouville theory are applied to solving the governing equations of the pile and soil, taking into account the interaction conditions between the pile and soil. Rigorous solutions are obtained for the twist angle and internal torque along the pile shaft, as well as the shear stress with depth provided by the surrounding soil. Validation of the present HSPI model by comparing with previous theoretical and experimental data indicates the applicability and superiority of the derived solutions. The HSPI model is subsequently applied to conduct extensive arithmetic examples for investigating the torsional response of piles accounting for complex soil heterogeneity patterns and pile configurations. The obtained results can contribute to a deeper understanding of the operational mechanics involved in torsionally loaded piles in heterogeneous soil.