Analysis of Behavior of Sand Surrounding Pile Tips

Abstract

A finite-element approach is presented to predict the behavior of dense sand surrounding the pile tip in a fairly large stress range, from low stress levels to very high ones, where particle breakage occurs. The approach is based on a constitutive model for sand, which is characterized by critical-state–type yield surfaces and by a nonlinear Mohr-Coulomb failure criterion, the latter being defined on the basis of constant-volume shear strength and of dilatancy. In addition, the concept of constant relative breakage surfaces, which represent families of curves characterized by constant amounts of particle crushing, is introduced. It is shown that the model, applied to the analysis of the behavior of the tip of nondisplacement piles in sand, can be used to visualize and to predict the distribution of strength, dilatancy, and grain breakage in the soil surrounding the pile base.