Reinforced embankments over soft foundations under undrained and partially drained conditions

Abstract The behaviour of geosynthetic reinforced embankments constructed on soft cohesive foundations under undrained and partially drained conditions is examined using an elliptical cap soil model. Consolidation is modelled using Biot theory. The effects of reinforcement stiffness, partial consolidation of the foundation soil during embankment construction and foundation soils with different initial undrained strength profiles are examined. Particular attention is focused on the strains in the geosynthetic reinforcement at working conditions and at embankment failure. The effect of reinforcement on the deformation of the foundation soil is evaluated. It is shown that reinforcement can significantly reduce the maximum lateral deformations, vertical deformation and foundation soil heave during embankment construction. For the conditions examined, partial drainage during construction provides an 11–38% increase in the factor of safety against failure of reinforced embankments relative to that expected under perfectly undrained conditions.

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