Dynamic pile‐soil‐pile interaction. Part II: Lateral and seismic response

Abstract A simplified three‐step procedure is proposed for estimating the dynamic interaction between two vertical piles, subjected either to lateral pile‐head loading or to vertically‐propagating seismic S‐waves. The starting point is the determination of the deflection profile of a solitary pile using any of the established methods available. Physically‐motivated approximations are then introduced for the wave field radiating from an oscillating pile and for the effect of this field on an adjacent pile. The procedure is applied in this paper to a flexible pile embedded in a homogeneous stratum. To obtain analytical closed‐form results for both pile‐head and seismic‐type loading pile‐soil and soil‐pile interaction are accounted for through a single dynamic Winkler model, with realistic frequency‐dependent ‘springs’ and ‘dashpots’. Final‐ and intermediate‐step results of the procedure compare favourably with those obtained using rigorous formulations for several pile group configurations. It is shown that, for a homogeneous stratum, pile‐to‐pile interaction effects are far more significant under head loading than under seismic excitation.