Abstract
During the last decade the offshore wind industry grew ceaselessly and engineering challenges continuously arose in that area. Installation of foundation piles, known as monopiles, is one of the most critical phases in the construction of offshore wind farms. Prior to installation a drivability study is performed, by means of pile driving models. Since the latter have been developed for small-diameter piles, their applicability for the analysis of large-diameter monopiles is questionable. In this paper, a three-dimensional axisymmetric pile driving model with non-local soil reaction is presented. This new model aims to capture properly the propagation of elastic waves excited by impact piling and address non-local soil reaction. These effects are not addressed in the available approaches to predict drivability and are deemed critical for large-diameter monopiles. Predictions of the new model are compared to those of a one-dimensional model typically used nowadays. A numerical study is performed to showcase the disparities between the two models, stemming from the effect of wave dispersion and non-local soil reaction. The findings of this numerical study affirmed the significance of both mechanisms and the need for further developments in drivability modeling, notably for large-diameter monopiles.
Highlights
In the area of renewable energy, offshore wind occupies an eminent position
The pile description is based on the Love-Tismohenko theory for thin cylindrical shells and the non-local soil reaction is formulated as a convolution integral of local soil reaction models and the Gaussian function as spatial kernel
A onedimensional model, according to widely adopted approaches in the area of pile driving, is formulated and used for comparison, in order to investigate the effects of dispersion of elastic waves and non-locality of soil reaction
Summary
In the area of renewable energy, offshore wind occupies an eminent position. Since the onset of offshore wind farm construction, monopiles constitute the dominant foundation concept used in shallow and intermediate water depths [1,2]. Local and frequency-independent springs and dashpots are arranged together with non-linear elements, e.g., frictional sliders, to represent the soil reaction during installation. In the advent of large-diameter monopiles, used in offshore wind, the validity of the existing approaches to analyse pile drivability was examined. Since the spectrum of frequencies excited in the pile during a hammer impact may pertain in the range in which dispersive effects are not negligible, a more accurate description of the pile structure is required. The effect of non-local dynamic soil reaction is introduced, by formulating a non-local foundation model based on the stiffness and damping parameters of its local counterpart. To demonstrate the effects of the aforementioned mechanisms, a one-dimensional pile driving model with local soil reaction, as customarily used in engineering practice, is formulated and a numerical study is performed to compare the two approaches.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
