This paper describes an integrated study of the mechanical behaviour of normally consolidated cohesive soils，by means of a series of triaxial tests on cohesive soils covering a wide range of plasticity index，and centrifuge model tests on failure of embankments constmcted on cohesive soils．
Results of the triaxial tests show that strength anisotropy and strain anisotropy become more marked for soils with a lower plasticity index．In the centrifuge test，significant lateral deformation due to embankment loading was observed in soil with a low plasticity index．In addition，an attempt was made to provide likely explanations by Finite Element Method analysis．The numerical method proposed in this paper is a simple procedure which predicts with sufficient accuracy，the actual deformation of a deep clay foundation under embankments，although a number of simplifing assumptions have been made in terms of the soil parameters and defomation analyses．It is concluded that this method can be used as a preliminary design in engineering Practice．