Lateral displacement behaviour of spun piles embedded in fill layer over soft soil using 3D finite element analysis

This paper evaluates the displacement behaviour of spun piles under lateral load in uniform fill layer overlying soft soil through three-dimensional finite element method. The numerical model is initially verified through the field measurement from the lateral pile test by adopting the solid and embedded beam (spring) element model approach. The results showed that both approaches could accurately simulate lateral pile behaviour, with the solid element offering more detailed soil–structure interaction and the embedded beam model offering computational efficiency with adequate accuracy. The parametric study demonstrates that the upper fill layer above the pile fixity point plays a major role in controlling lateral displacement, while pile diameter and load eccentricity significantly influence spun pile performance, especially in more flexible, thinner-walled piles. Furthermore, a simplified method is proposed to estimate the fixity point of a laterally loaded pile and was validated using field observations from various pile case histories.