A new constitutive model for time-dependent behaviour of soft soils has been recently proposed. Stemming from a previously developed viscoelastic isotropic model based on ellipses of Modified Cam Clay, anisotropy was taken into account by introducing a fabric tensor to represent the rotation of the constitutive ellipses in p'-q (mean effective stress-deviatoric stress) plane. Due to the particle orientation induced by deposition mechanism, natural soils are anisotropic in terms of strength and stiffness. The improvement induced by the new formulation is particularly evident in stress paths in extension. The new soil constants required by the anisotropic formulation need no calibration, since they can be expressed in terms of parameters already used in the isotropic model and familiar to practicing geotechnical engineers. In this paper, the numerical analysis of an embankment on soft soils has been carried out, in order to investigate on the differences in terms of predictions of vertical and horizontal displacements between the isotropic and the anisotropic creep model.