A rigorous elastoplastic load-transfer model for axially loaded pile installed in saturated modified Cam-clay soils

Most currently available load-transfer models for axially loaded pile are either highly empirical or oversimplified without rigorous theoretical manner. This paper presents a novel and rigorous load-transfer model for axially loaded piles installed in modified Cam-clay (MCC) soils under undrained loading. The model is formulated in terms of the Lagrangian description based on the rigorous deformation mechanism of the soil around the pile shaft during undrained loading. Considering the boundary conditions and the equilibrium state of the soil, a t–z curve is extracted from the well-established MCC model that is employed to represent the elastoplastic behaviour of soil surrounding the pile. The proposed model is compared with a well-established finite element model and applied to predict the load–displacement behaviour of two well-documented piles to manifest the validity and capability of the model. The results demonstrate that the present theoretical model can well predict the elastoplastic load–displacement response of the pile and is capable of reflecting some important phenomena observed from pile load tests. The present model provides a rigorous, practical, and effective approach for estimation of the load–displacement behaviour of frictional piles installed in clayey soils.