Numerical and Experimental Evaluation of Axial Load Transfer in Deep Foundations Within Stratified Cohesive Soils

Abstract

This study presents a numerical and experimental evaluation of axial load transfer mechanisms in deep foundations constructed in stratified cohesive soils in & Idot,zmir T & uuml,rkiye. A full-scale bi-directional static load test equipped with strain gauges was conducted on a barrette pile to investigate depth-dependent mobilization of shaft resistance. A finite element model was developed and calibrated using field-observed load-settlement and strain data to replicate the pile-soil interaction and deformation behavior. The analysis revealed a shaft-dominated load transfer behavior with progressive mobilization concentrated in intermediate-depth cohesive layers. Sensitivity analysis identified the undrained stiffness (Eu) as the most influential parameter governing pile settlement. A strong polynomial correlation was established between calibrated Eu values and SPT N60 offering a practical tool for preliminary design. Additionally strain energy distribution was evaluated as a supplementary metric enhancing the interpretation of mobilization zones beyond conventional stress-based methods. The integrated approach provides valuable insights for performance-based foundation design in layered cohesive ground supporting the development of site-calibrated numerical models informed by full-scale testing data.