Lateral behavior of monopiles under the simultaneous effect of vertical-lateral loads and change of embedment depth due to 1D local scouring

Abstract

Offshore wind turbine foundations are subjected to high lateral loads but insignificant vertical forces of the superstructure. A decrease in the embedment depth due to scouring can also alter the effect of vertical loads on the soil-structure interaction. Current design methods consider the vertical and lateral forces in design separately. This area also lacks studies featuring physical modeling that produce consistent conclusions. The present study employed centrifugal physical modeling to investigate the lateral behavior of offshore wind turbine monopiles under the simultaneous effects of vertical and lateral loads with a change in embedment depth caused by 1D local scour (D = diameter of pipe) in calcareous sand. The results showed that the vertical load of the superstructure increased the lateral strength of the monopile in the no-scour and local scour cases by about 3.5% and 6%, respectively. Improvements in the p-y curves along the embedment depth were noted at depths of less than twice the monopile diameter. Stress intensification was more significant under the scoured conditions because of the reduced embedment depth of the monopile. Overall, the vertical superstructure loads had little effect on the lateral performance of the monopiles.