Assessing the Potential of Numerical CPTs to Improve the Geotechnical Characterization of Offshore Sites: Case of the Italian Sea

Abstract

The paper presents the results of large deformation finite element analyses of laboratory and site cone penetration tests (CPTs) in sand. The numerical model implements the Arbitrary Lagrangian-Eulerian formulation and hypoplastic constitutive model to reproduce the soil response. Available laboratory CPTs conducted in dense sand within a large-scale testing facility were used to calibrate the model and to assess its ability to reproduce the cone penetration mechanisms and to explore the effect of variation in the cone size. The approach, as validated, was then applied to reproduce CPT tests carried out in the Italian offshore. Within the scope, new parameters were identified for the soil model using routine test data. The model was shown to successfully reproduce the profiles of cone resistance as collected on-site, also in the presence of local variation of soil density, assessing the modeling procedure as a whole and providing the basis for broader applications related to the study of large deformation problems in the offshore environment, such as those concerning foundation installation. The model also allows for verifying the consistency of CPT-based empirical correlations, such as the relative density and the peak friction angle, improving confidence in their use in design. The outcomes of the work also show how geotechnical site information collected in the past can be turned into a practical tool to support the geotechnical design of new offshore developments, supporting, in a practical way, the transfer of knowledge from the oil and gas to the renewable energy market.