Vertical transient loading of a suction caisson in dense sand

Suction caissons are hollow cylinders open towards the bottom currently used as anchors for deep water offshore facilities. They recently turned out to be advantageously exploited as foundation for offshore wind turbines in shallow water (Senders 2009). The Prevost model for cohesionless soils (Prevost 1985) is adapted for the modelling of their cyclic behaviour. It is able to reproduce plastic deformation in both loading and unloading, contractancy of the soil and pore pressure build up as well. In this paper, a fully-coupled transient axisymmetric analysis of a suction caisson is carried out. The monotonic partially drained behaviour of the caisson is firstly highlighted. Afterwards, pseudo-random and sinusoidal-equivalent storm signals are compared. Permanent displacements accumulated at the end of the storm show a good agreement between them but are slightly divergent, which indicates that the position of the extreme event might be a relevant issue