A Theoretical Framework for Predicting Soil Setup in Laterally Loaded Piles in Clay

Soil setup is known to enhance the capacity of jacked piles and is well documented for axial resistance, but its influence on lateral behavior and corresponding evaluation methods remain limited. In this study, a new theoretical framework is proposed to estimate the time-dependent lateral response of closed-ended piles in normally consolidated clay by jointly considering installation-induced disturbance and subsequent consolidation. The framework couples cavity expansion theory with an effective stress approach to capture the evolution of pore pressure, effective stress and strength from installation through reconsolidation, and to quantify the attendant changes in pile–soil interaction. Its performance is demonstrated against finite-element simulations and a field experiment, showing close agreement. Results reveal a strong link between lateral capacity gain and the dissipation of excess pore pressure. Parametric studies further show that rigid piles experience significantly greater capacity improvements than flexible piles, as their associated soil flow mechanisms enable the mobilization of a wider zone of strength-enhanced soil. In addition, increasing pile diameter prolongs the dissipation of excess pore pressure and thus the setup process. While the setup effect for laterally loaded piles is generally less substantial than that widely reported for axially loaded piles, especially for flexible piles, the present framework offers a useful means of evaluating its influence in applications where lateral stiffness and deformation are particularly sensitive and govern performance.