Engineers Australia

CPT-based design of foundationsE.H. Davis Memorial Lecture 2017

B. M. Lehane

Abstract

The Cone Penetration Test (CPT) is now the most popular in-situ test used worldwide, largely due to its ability to provide continuous and reliable soil profile information in a rapid, cost-effective and digital format. This paper shows how the CPT end resistance (qt) can be used directly in foundation design without the need for intermediate and often subjective interpretation of soil parameters. A simple model illustrating the relative effects of factors controlling the magnitude of qt is first described to provide a basis for correlations between qt and aspects of foundation performance. The development of a variety of design formulations for deep & shallow foundations and walls is then described. It is demonstrated that allowance for previously unaccounted for geometric and other effects greatly enhances the reliability of these formulations compared with previous CPT-based methods.