Improved Relationships for the Pile Base Response in Clayey Soils

Abstract

Recent research on the topic of pile base resistance has demonstrated that the guidelines provided by existing design manuals and codes are rather conservative in the case of clayey soils under undrained conditions. With the aim of investigating this topic more rigorously, a computationally intensive study was carried out to quantify the effect of the soil rigidity index on the response of pile base resistance. A precise assessment of the results led to the formulation of hyperbolic relationships that capture the development of the base resistance as a function of settlement. The relationships were implemented in a beam column analysis and validated against a full axisymmetric numerical analysis and also with respect to field data from a pile test performed using an Osterberg cell near the pile base. The validation process demonstrated the usefulness of the method and recommendations arising with respect to mobilization of the pile base resistance. This study should, therefore, assist in the development of more scientifically based guidelines for pile design that balance safety and economy.