Measurement of shear wave velocity in marine sediments

Abstract

This presentation describes the shear wave velocity measurement techniques that have been utilized over that past decade at the Marine Geomechanics Laboratory (MGL) at the University of Rhode Island (URI). The shear wave velocity of marine sediments is of interest to both the underwater acoustics and marine geotechnical engineering communities. In underwater acoustics, sediment shear wave velocity plays an important role in understanding compressional wave attenuation. Geotechnical engineers utilize shear wave velocity, for example, for the analysis of seismic site response and evaluation of soil liquefaction potential. The shear wave measurement techniques that will be covered include laboratory bender element tests made within the triaxial apparatus that allows for the application of situ stress states on the test specimen. Bender elements have also been used in the lab to make shear wave velocity measurements in reconstituted sand fills at very low stress levels, as well as on intact clay sediments directly within a piston core. More recently, field measurements of shear wave velocity have been made using a system developed by colleagues at URI that involves the measurement and inversion of Scholte waves. The presentation aims to stimulate dialog between the fields of underwater acoustics and marine geomechanics on the topic of shear wave velocity.