Influence of residual stress and soil dilatancy on the load capacity of jacked pile

Pile jacking is one of the commonly adopted techniques for installation of displacement piles. The present study investigates the evolution of residual stresses during the pile jacking process and its subsequent impact on the pile load capacity with a particular emphasis on the soil dilatancy angle. The simulations have been carried out following an updated Lagrangian-based finite element framework employing ABAQUS. The magnitude of radial to vertical residual stress ratio coincides with the passive earth pressure coefficient within a radial zone of 6D and reduces to the at-rest coefficient beyond 20D. Owing to the enhanced stress-state, the load capacity of jacked pile is markedly higher than the in-place one with a predominant contribution from the shaft resistance. A small increase in soil dilatancy results into significant enhancement of residual radial stress and extent of influence zone, which further leads to increased load capacity in jacked pile through enhanced shaft resistance.