Experimentelle Untersuchung der Verformungsakkumulation eines Flachgründungsmodells von Offshore-Windenergieanlagen

Experimental investigations on the deformations accumulation of a shallow foundation model for offshore wind turbines.

Foundations of offshore wind turbines are exposed to millions of load cycles during their service life. This cyclic loading can lead to settlements and rotations of the structure, affecting its serviceability. The behaviour of shallow foundations under such loading conditions has been rarely investigated so far. Thus, numerous experimental studies were performed on a small scale foundation model under horizontal cyclic loading. The focus of this contribution is on these model tests which were performed on dry fine sand. After a brief general introduction, the experimental setup is presented. It consists of a specially designed measuring and loading device, as well as a facility for the preparation of medium dense to dense samples. Afterwards the experimental results are presented. The settlement and rotation behaviour under single- and multi-dimensional loading as well as under multistage one-way loading was investigated. Furthermore, the behaviour after a single large wave event, like a so-called freak wave, was studied. Due to the subsequent cycle packages a reduction of rotations resulting from the strong event was observed. The influences on this backward rotation were investigated systematically. The effects of different load amplitudes, average loads, load directions and relative densities are discussed.