The effect of the yield and plastic potential deviatoric surfaces on the failure height of an embankment

The paper investigates the effect of the deviatoric shape of the yield and plastic potential surfaces on the failure height of an embankment founded on a soft clay deposit. Different combinations of the shapes of the surfaces in the deviatoric plane are explored in a critical state model that predicts isotropic strength, and which is used in order to model the clay foundation. The shapes considered start from the widely used circular shape and move on to the Mohr–Coulomb hexagon and advanced shapes, such as the Lade shape. For all combinations the same undrained strength profile in triaxial compression is adopted for the clay foundation. Finite element analyses investigate the failure height of the embankment assuming plane-strain conditions. Moreover, two ways of modelling the fill material are adopted in the analyses, and the effect of each of these on the failure height of the embankment is explored.