Effective friction angle of soft to firm clays from flat dilatometer

Abstract

A new method based on spherical cavity expansion theory is used to interrelate data from piezocone penetration tests (CPTUs) and flat plate dilatometer tests (DMTs) in soft to firm clays. Data from 27 clay sites are shown to confirm simple links that express the CPTU net resistance and excess porewater pressure in terms of th e DMT contact pressure and expansion pressure. As a result, the derived nexus is explored to predict the effective friction angle of soft to firm clays from DMT data using an existing CPTU limit plasticity solution. Two well-documented case studies are presented to illustrate the reasonable prediction of the effective friction angle in comparison with laboratory anisotropically consolidated undrained compression triaxial test results on undisturbed samples.