Student): NATALIA MOSCHEN BOTTECCHIA

Candidate for the Degree: Master in Civil Engineering from the Pontifical Catholic University of Rio de Janeiro (PUC-Rio)

Title: Offshore Wind Tower Foundations: Numerical Modeling of Monopile in Quartz Sand

Data: 20 September 2024

Working Hours: 10:00

Virtual Room:

 <https://teams.microsoft.com/l/meetup-join/19%3ameeting_NTk0MjcyZGUtMWQzMy00MmIyLTkyN2YtZTU3MTc1Y2E4MDkz%40thread.v2/0?context=%7b%22Tid%22%3a%225894b841-8b59-454b-8a26-648e79cf1997%22%2c%22Oid%22%3a%22169198b3-8420-410c-849a-b1dbb1642d93%22%7d>

Meeting ID: 239 586 176 080

Password: F9PboR

Summary: The increasing global concern for sustainable energy solutions has driven the development of offshore wind energy. In Brazil, it emerges as a promising renewable energy source, given its vast coastal potential. This study investigated the behavior of monopile foundations, widely used in offshore wind turbines, installed in quartz sand and subjected to monotonic lateral loading. Three three-dimensional numerical models were developed in the Plaxis 3D software, initially using the perfectly plastic elastic constitutive model of Morh Coulomb, followed by the advanced Hardening Soil model. The research was motivated by the limitations of the main standards, APl and DNV, originally developed for flexible foundations of oil and gas industry platforms, which do not adequately represent the behavior of monopiles. The analyses included the evaluation of deformed meshes, displacements in the axis of application of the load, shear deformations, principal stresses, plasticization points and load-displacement curves. Comparisons with experimental data from physical modeling in a geotechnical centrifuge revealed limitations in the simulation of the monopile stiffness and strength, attributed to the lack of simulation of the driving effects and the calibration of the constitutive models in inadequate triaxial conditions. In order to better reproduce the field behavior, it is proposed that the numerical model be replicated with the calibration of the constitutive models performed based on triaxial lateral compression tests. The difficulties encountered in the numerical modeling highlight the complexity in replicating the field conditions, requiring more sophisticated approaches. In addition, parametric analyses were performed as a function of the strength and stiffness, which indicated that the increase in these parameters results in greater lateral forces for the same level of lateral displacement.