Correlating the shear wave velocity with the cone penetration test

Abstract

The shear wave velocity VS is an essential parameter in various geotechnical analyses. It can be determined using laboratory testing of undisturbed samples, in-situ geophysical measurements, or by using correlations of the shear wave velocity with the common in-situ penetration tests such as the standard penetration tests (SPT) and the cone penetration test (CPT). The latter approach is often preferred by engineers for many reasons including cost optimization of the geotechnical investigations and infeasibility of undisturbed sampling in some formations such as non-cohesive soils. Accordingly, many correlations were envisaged to determine the shear wave velocity using the CPT; these correlations were developed through statistical and regression analyses of compiled CPT and shear wave velocity databases. Yet, to date, substantial discrepancies between the existing CPT correlations and the measured shear wave velocities are still revealed when the CPT correlations are compared with more recent case histories and databases. As such, there is a continuous need to update these correlations. In this study, a proposed approach is presented to define the stress-dependency parameters of the shear wave velocity in terms of the CPT measurements. Hence, enhanced CPT correlations for the shear wave velocity and the small strain modulus in both cohesionless and cohesive soils are realised. Two case studies are analysed using the proposed CPT correlation for the shear wave velocity as well as the commonly applied correlations. It is shown that the proposed CPT-VS correlation provides consistent predictions with the measured shear wave velocity; hence, it may be considered as an enhancement to the currently adopted methods.