Practical considerations for numerical simulation of large-diameter monopiles for offshore wind turbines in overconsolidated sand: A case study of the VIBRO project in Cuxhaven, Germany

Monopiles are typically the preferred foundation for offshore wind turbines, which are becoming increasingly large. While 3D finite element modelling can aid the design process of monopile foundations, achieving reliable results requires precise constitutive soil models and input parameters derived from laboratory and field data, as well as careful consideration of soil sample preparation method. This study explores various soil preparation methods, including moist tamping, dry tamping, and air pluviation, along with two sample ratios (1 and 2) during triaxial tests. It uses an advanced soil model, the DeltaSand model, and a practical industry model, the Hardening Soil model with small strain (HSsmall). To evaluate model performance, the Vibro project performed in Cuxhaven, Germany, is used as a case study. Simulations using the DeltaSand model show good agreement with field data. The effects of soil preparation methods and sample ratios are more pronounced in HSsmall model simulations, in which better results are obtained when the model is calibrated using dry tamping data and a sample ratio of one. • Reconstitution methods and H/D ratios impact. • Comparison of HSsmall and DeltaSand models for predicting monopile capacity.