Axisymmetric transient modelling of a suction caisson in dense sand

Suction caisson are hollow cylinders open towards the bottom that are 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 currently used for the modelling of their cyclic behaviour. It’s 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. A vertical pseudo-random loading is transformed into equivalent ones. Comparison of the permanent displacement accumulated shows a good agreement between them. The influence of the interface conditions is also addressed. For low tension amplitude applied to the caisson, it can be modelled as “stuck” to the inner soil. However higher amplitude might lead to a total unplugging