Analysis of bearing capacity and deformation of offshore wind power monopiles based on field test pile experiments

To address the reliability of design parameters for monopile foundations in offshore wind farms located in deep soft soil strata, this paper systematically analyzes the bearing capacity and deformation characteristics of large-diameter monopiles under horizontal, vertical compressive, and uplift loads based on field pile load tests conducted in Hangzhou Bay. In situ piezocone penetration test (CPTU) are used to determine soil strength parameters, and a 3D finite element model is established to compare the applicability of the Mohr-Coulomb and HSS constitutive models, and the method for determining soil stiffness parameters is optimized. The results show that: (1) The elastic moduli obtained from laboratory soil tests are significantly lower than the CPTU-interpreted values, leading to larger deviations in pile head displacement predictions; (2) The shallow silty clay dominates lateral bearing capacity, while mid-depth sandy soil controls vertical bearing behavior; (3) The use of CPTU-interpreted soil parameters can effectively improve the accuracy of numerical simulations. The proposed methodology (integrating in situ testing, parameter optimization, and multi-load case validation) provides a theoretical basis for monopile foundation design in offshore wind projects.