A unified CPT–SPT correlation for non-crushable and crushable cohesionless soils

Despite the continuous developments in the Cone Penetration Test (CPT), the Standard Penetration Test (SPT) is still used extensively in site investigations. Hence, there is a constant need to update the CPT–SPT correlations to make use of the growing experience with the CPT. Many CPT–SPT correlations have been proposed based on case histories of predominantly quartzitic/ non-crushable sands; yet, more efforts are needed to enhance their reliability. Additionally, recent studies were carried out on calcareous/crushable sands have shown that the common CPT–SPT correlations for these sands are even less reliable than they are for quartzitic sands. In this study, a proposed approach is presented to define the related soil compressibility parameters of the CPT–SPT correlations. The presented methodology enhances the reliability of the CPT–SPT correlations and provides a unified approach encompassing both crushable and non-crushable sands.