Relative density prediction based on in-situ and laboratory measurements of shear wave velocity

Extensive laboratory and in-situ testing has been carried out in an onshore test site on the North Sea Coast near Cuxhaven, Germany. The test site was chosen due to initially high cone resistance (>30 MPa) in sand and close stratigraphic links to soil conditions for North Sea offshore wind projects. The in-situ program included cone penetration testing, geophysical downhole logging and sampling. A correlation between relative density, shear wave velocity and mean effective stress is proposed based on laboratory measurements with bender elements under anisotropic stress conditions. The proposed correlation is applied to in-situ shear wave velocity data and compared with relative density estimated based on density logs and recognized empirical CPT correlations. Taking the density logging as a reference, the new correlation provides comparable ac-curacy range as the existing empirical CPT-based relations although with a slight tendency for underestimation. This novel correlation could be used as an alternative and conservative verification procedure for the relative density of sands.