In situ shear wave velocity from multichannel analysis of surface waves (MASW) tests at eight Norwegian research sites

The Multichannel Analysis of Surface Waves (MASW) technique, used
to determine shear wave velocity (Vs) and hence small strain stiffness (Gmax), has
recently generated considerable interest in the geophysics community. This is because
of the ease of carrying out the test and analysis of the data. The objective of this work
was to assess the repeatability, accuracy and reliability of MASW surface wave
measurements for use in engineering studies. Tests were carried out at 8 wellcharacterised
Norwegian clay, silt and sand research sites where Vs had already been
assessed using independent means. As well as being easy and quick to use MASW
gave consistent and repeatable results and for the clay sites the MASW Vs profiles
were similar to those obtained from other techniques. Reasonable results were also
obtained for the silt and sand sites, with the best result being obtained for the finer silt.
This work also confirms that MASW Vs clay profiles are comparable to those
obtained by correlation with CPT. For these sites there also seems to be a good
correlation between normalised small strain shear modulus and in situ void ratio or
water content and the data fit well with published correlations for clays.