Assessing potential cracking zones in embankment dams

Internal erosion and piping is the cause of about half of large embankment dam failures. Most internal erosion and piping failures occur due to concentrated leak erosion which is initiated by a crack in an embankment or its foundation. Differential settlements occur due to the variations in the height of the embankment across the valley in which the dam is constructed. This can lead to low stress and tensile strain zones in which cracks may form. This paper presents two dimensional numerical analyses of the deformations and stresses in the cross valley profile during construction, and assesses the potential cracking zones. These analyses are based on the use of the commercial finite element software ABAQUS and staged construction simulation is incorporated in the models. It is shown that tensile and low stress zones form at the crest of the dam near the abutments, and large tensile strain zones may occur over discontinuities and irregularities in the cross valley profile. A parametric study has been carried out to assess the effect of the abutment slope, step width and height on these potential cracking zones.