A FEM Assessment on the use of t-z and q-z Functions for Deep Foundations

Abstract

Load-movement t-z and q-z functions have been established and widely accepted as a tool to characterise pile shaft and toe resistances respectively. The functions are best used to represent a short element along the pile. But the question remains whether these functions depend on pile diameter and pile depth. This paper discusses the soil-structure interaction and load transfer mechanisms of a single pile and reviews the theoretical basis of the t-z and q-z functions. The bearing behaviour of a single circular footing under various conditions was also investigated and compared against the toe behaviour of piles. Linear elastic and Mohr-Coulomb soils are used for this study to investigate stress versus normalized movement curves for pile behaviour.