With the offshore wind industry rapidly expanding worldwide, geotechnical research is being devoted to foundation optimisation – most intensively for large-diameter monopiles. The analysis and design of monopiles still suffers from significant uncertainties in relation to cyclic/dynamic loading conditions. This work aims to shed new light on dynamic soil-monopile interaction, based on the results of unique full-scale experiments performed at the Westermeerwind wind park (Netherlands). The response of a 24 m long, 5 m diameter monopile to harmonic lateral loading of varying amplitude and frequency is inspected. The analysis of original field measurements (soil accelerations and pore pressures) enables to link the lateral stiffness observed at the monopile head to dynamic effects occurring in the surrounding soil. The interpretation of measured data is supported by three-dimensional finite element studies, also looking at the influence of drainage conditions and monopile size. The set of results presented supports the need for dynamics-based monopile design as higher frequencies gain relevance in most recent offshore wind developments.
|Journal||Geotechnique: international journal of soil mechanics|
|Publication status||E-pub ahead of print - 2020|
- piles & piling
- full-scale tests
- soil-structure interaction
- finite-element modelling