Axisymmetric transient modelling of a suction caisson in sand: a numerical study

This paper deals with the axisymmetric behaviour of a suction caisson installed in sand upon
vertical monotonic and cyclic loading. A steel caisson is numerically modelled using the finite element code
LAGAMINE. The Prevost model reproduces the cyclic behaviour of the soil, i.e. it captures the accumulation
of deformation and pore water pressure within the soil. Coupled interface finite elements allow the modelling
of the uplift behaviour of the caisson in both drained and partially drained conditions. Upon compression or
traction loading, the suction caisson presents different modes of resistance: friction along the shaft, bearing capacity
under the lid or the tip of the caisson, suction effect. The first part of this work describes the progressive
mobilisation of these modes of resistance during monotonic simulations. The partially drained effect is particularly
interesting since it drastically increases the resistance to transient loading. It proceeds from the transient
consolidation process induced by the caissons loading. The second part describes the evolution of the settlement
of the suction caisson upon different kind of cyclic loading signals.