CPTU CORRELATIONS FOR CLAYS

As part of the R&D project GEODIP-SP8, a multivariate high-quality database of sensitive clays consisting of laboratory strength and consolidation test results, index parameters and CPTU parameters was established. The present report evaluates, with the help of multiple regression analyses, possible correlations among measured CPTU parameters (e.g. excess pore pressure, Δu, net cone resistance, qnet, and effective cone resistance, qe), undrained shear strength from CAUC tests (suC) and some basic clay properties (e.g., OCR, plasticity) included in the database. The first part of the report presents the collected data points and it discusses sample quality. Then, correlations based on simple and multivariable linear regression analyses are proposed for undrained shear strength, overconsolidation ratio and preconsolidation stress. The goodness of the established correlations established is checked for seven test sites in Norway. Finally, recommendations for engineering practice are given based on the outcomes of this study