The failure of an embankment during its construction on soft clay foundation is investigated. Field and laboratory data are used in conventional slope stability analyses to explain the cause of the failure and to evaluate the in-situ undrained shear strength of the clay which was later used in the design of the replacement dike. The results indicate that whereas the stiff embankment having a well compacted core was initially stable on the soft clay, subsequent cracking of the core due to undrained deformations reduced the shearing resistance of the dike thus, initiating the failure. The dike was eventually reconstructed in stages allowing enough time between stages for the foundation clay to consolidate and increase its shear strength. In the new dike a granular material was used in order to provide flexibility and to prevent cracking of the dike. In addition, long berms were placed on both sides of the dike to increase its stability. Field instruments including piezometers and inclinometers were used to monitor the rate of the stage construction of the new dike
