A number of embankment founded on soft clays have become unstable during construction of a major highway project in Malaysia. One of the embankment was back analysed based on its geometry before the failure. Measured in-situ vane shear strength was used in total stress analysis to determine the factor of safety at failure. Performance of the soft clay subsoil with regards to vertical and horizontal displacements, and piezometric response, when the failure was imminent is also described