Load-Deformation Mechanism for Bored Piles

An elasticity model based on the finite element method is developed for analyzing the mechanisms which govern the behavior of bored piles in stiff clay. The method can be used to predict accurately the load capacity and load-deformation behavior of a single pile. A trilinear approximation of the stress-strain curve obtained from undrained triaxial tests is used. The formation of a tension crack which develops at the tip of the pile is shown, invalidating the classical plasticity solutions for tip capacity. The usual assumption of adhesion failure occurring at the pile-soil interface is supported. Comparison of the theoretical results with field measurements on five large-diameter test piles shows the accuracy of the method.