LAUSR

The p-y method according to the offshore guidelines is usually applied for the design of laterally loaded piles. However, a number of modified p-y approaches for piles in noncohesive soils were proposed in the recent years to account for the effect of the pile diameter. These approaches were developed for piles in homogeneous soil but are used in current engineering practice for piles in layered sand as well. Concerning this matter, this paper presents a comparative evaluation of the existing p-y approaches for piles in layered sand by means of three-dimensional numerical simulations. Two large-diameter piles in widely varied layered sand representing a monopile and a pile of a lattice structure for the foundation of an offshore wind energy converter are considered. It is demonstrated that the effect of the layering is limited; that is, the deviations of the analytical results from the numerical results are predominantly associated with the deviations obtained for homogeneous sand. An occasionally used overlay procedure to adapt the p-y curves depending on the adjacent soil layers is shown to have not only a small impact on the analytical results but also some major deficiencies with regard to a reliable consideration of the layering.