Vergleich von Ansätzen zur Prognose der Langzeitverformungen von OWEA-Monopilegründungen in Sand - Teil 2: Simulationen und Schlussfolgerungen

Comparison of methods for the prediction of long-term-deformations of OWEA monopile foundations in sand

In the process of renewable-energy-development the number of offshore wind parks in the North Sea and the Baltic Sea increases. The offshore wind power plants are often founded on a single large pile, a so-called monopile. The cyclic loading due to wind and waves causes an accumulation of deformation in the soil which may lead to a permanent tilting of the monopiles. Different methods have been developed for the prediction of these non-linear long-term deformations.
In this study the predictions made by the various methods are compared for realistic dimensions and loadings of an offshore wind power plant as well as different densities of a non-cohesive soil. The quality and the limitations of the methods were examined. The following methods were studied: the P-y-curves of the American Petroleum Institute (API), a method proposed by Dührkop, the ESWM by Tašan et al., the SDM by Achmus et al. and a method which is used at the IBF (KIT), here referred to as HIA.
The calibration of the parameters of the various methods is presented in [5]. In this paper the pile displacements predicted by the different methods are compared with each other. The implementation of these methods and the applied loads are explained before the results are presented. Although the model parameters were determined for the same fine sand and in some cases were obtained using the same experimental results, large differences are observed between the predictions given by each method.