Failure Mechanisms in Granular Embankments on Purely Cohesive Clay

Abstract This study adopts an elastic–plastic finite-element approach with strength reduction to investigate the stability of granular embankments over undrained clay, with application to the short-term stability assessment of this embankment at the end of construction. The focus is on the critical dimensionless strength of the foundation at which the failure mechanism will change from deep to translational. It is shown that the critical dimensionless strength is related to the effective friction angle of the embankment layer, the foundation depth ratio, and the slope angle. Comparisons of factors of safety across methods are also made, showing that a deep failure mechanism may lead to unconservative results if the dimensionless strength of the foundation exceeds a critical value.