A qualitative study on the lateral behavior of rock-socketed monopiles

Monopile supporting offshore wind turbines (OWT) in regions with shallow rock can benefit from rock-socketing. This study qualitatively investigates the effect of the rock layer on the serviceability limit state (SLS) and the ultimate limit state (ULS) of the monopiles. A nonlinear three-dimensional finite element model was constructed to simulate monopile–soil interaction and was validated using data from centrifuge experiments. The effect of the rock-socketing was analyzed for three cases flexible, semi-rigid and rigid, and compared with conditions in pure sand. The results are presented in terms of the limit state selection, lateral capacities, lateral deformation modes, soil deformation patterns, lateral earth pressure distribution and soil reaction curves (p-y). The finding indicates that rock-socketing significantly affects the lateral responses for semi-rigid and rigid monopiles, while its impact on the flexible monopiles is minimal. Furthermore, the study highlights the need to develop a generalized lateral earth pressure distribution for the simplified lateral response prediction of rock-socketed monopiles.