Effect of pore fluid on the cyclic behavior of laterally loaded offshore piles modelled in centrifuge
The common practice in centrifuge modelling of dynamic processes is to use high viscosity pore fluids to unify the time scaling factors for the generation and dissipation of pore pressures. This paper focuses on the effects of the density and viscosity of the pore fluid on the behaviour of an offshore rigid pile subjected to cyclic and monotonic lateral loads. The soil used in these tests is dense sand and it was saturated with three different fluids: 1) water, 2) mixture of glycerine and water, 3) a fibre based viscous fluid with a density very close to that of water. The results of the tests in terms of the changes in the pore pressures at the interface of the pile and soil as well as monotonic lateral bearing capacity of the pile are compared. The tests illustrate that the behaviour of the model with water is very similar to that of the dry model, implying a fully drained behaviour. Moreover, it was observed that the density of the pore viscous fluid plays a major role in the evolution of the pore pressures. Therefore, it affects directly the stress state of the soil in the model.