Synthesis of a robust yet easy to implement method for site specific correlation between Offshore Piezocone Penetration Test data and Shear Wave Velocity

Seismic CPT (SCPT) is a versatile geotechnical investigation tool primarily used for determining shear wave velocity (Vs ) and hence small strain shear modulus (Gmax ) in the context of offshore foundation design and installation. The technique can be complex offshore, is time consuming and costly. SCPT are normally performed at selected locations in a survey area, whilst elsewhere within the site, correlation with PCPTdata is often performed to complete the ground model. Empirical correlations between PCPT and Vs have been established by various authors, usefully attempting to apply to all soil types / geological conditions orinclude soil-type specific variables to achieve this function. This is observed to occasionally lead to significant variance from measured Vs . The authors provide a critical review of published correlations using high quality SCPT and PCPT data and demonstrate the improved reliability of generating a nuanced site-specific correlation using an easily implemented multiple linear regression function. The method allows for the unique geology in a survey area to be accommodated and allows for more robust seismic correlation across a site. Finally, recommendations are given for the most appropriate site investigation and data interpretation methods for obtaining high quality SCPT data to calibrate the correlation.