Numerical investigation of the correlation between the complete anisotropic stress–strain curves and the CPTu response of marine clays

The cone penetration test (CPT) is widely used in offshore geotechnical engineering, with growing interest in directly deriving soil responses such as p–y curves for monopiles, to reduce the need for advanced laboratory testing. This requires reliable relationships between the CPT response and the underlying soil stress–strain behaviour. To investigate this link, CPT penetration in clay is simulated using the total-stress-based NGI-ADPSoft constitutive model. It is validated against data from the Tiller-Flotten test site in Norway. A parametric study further demonstrates how the complete anisotropic stress–strain response affects the simulated CPT response, by examining anisotropic shear strength, post-peak softening, small-strain stiffness, nonlinear hardening behaviour, and strain-rate effects. Anisotropy affects cone resistance through the unequal contributions of different stress paths, producing an approximately 13% difference from the isotropically averaged case for the case considered. Both residual strength and softening rate significantly affect cone resistance. A Norwegian marine clay database is then used to construct stress–strain curves, with overconsolidation ratio (OCR) as a representative soil-state parameter. The potential for inferring the underlying stress–strain characteristics from CPT measurements and the associated uncertainties are discussed, providing insights relevant to the future development of database-informed CPT-based p–y curves.