Novel semi-analytical model for the transient response of laterally loaded pile considering geometric nonlinear behaviors

Abstract

This paper presents a semi-analytical model based on the radiant stress theory for analyzing the transient response of pile foundations under impulse loading. Geometric nonlinear behaviors at the pile-soil interface, including the sliding and debonding, are properly considered through the introduction and implementation of the mixed boundary conditions. Laplace transform and Durbin inversion algorithm are employed to calculate the transient response of the laterally loaded pile in the time domain. An iterative strategy is proposed to determine the depth range of geometric nonlinearity. Comparison with the results from finite element method confirms the reliability of the semi-analytical model and demonstrates the significance of incorporating the geometric nonlinearity. Neglecting such nonlinear behaviors can lead to an underestimated pile displacement amplitude and a significantly overrated radiation damping, thereby eliminating the rebound phase and potentially resulting in an overdamped response. Furthermore, extensive parametric analyses are conducted to investigate the influences of modulus ratio, impulse duration, and pile slenderness ratio on the transient response of pile. The numerical results show that neglecting geometric nonlinearity tends to diminish the influences of modulus ratio, while high-frequency impulse loading leads to amplified rebound and re-impact phenomena. The semi-analytical model may serve as an efficient and accurate tool for analyzing and optimizing pile foundation design, offering a practical alternative to computationally more intensive numerical methods.