Author(s): Al-Riffai; Orendorff; Nistor; Rennie; St-Germain

Linked Author(s): Ioan Nistor

Keywords: No Keywords

Abstract: This paper presents results from an extensive experimental program on dam breaching mechanics and focuses on the erosion and side-slope instability of the breach channel that occurs on the downstream face of an embankment dam. The experimental work was conducted on homogeneous (non-cohesive) embankment models (30 to 60cm in height). Eight dam models were breached: four embankments with different soil compaction efforts, two embankments with different downstream toe drainage systems (inverted horizontal toe-drain filter vs. no drain) and two embankment dams with different soil compaction using the selected drainage system. It was found that a lower degree of saturation and a higher compaction can delay the breaching process significantly. Results for the different toe-drainage systems reinforce their importance as a model component in laboratory-scale testing for dam breach modeling and must therefore be incorporated in any physical model in order to obtain a realistic simulation of the outflow (breaching) hydrograph. In numerical simulations, capturing the influence of the unsaturated soil conditions above the infiltration curve through the embankment dam during the drawdown of the reservoir will require careful modeling of the shear strength of the soil, as well as of the critical Shield's parameter for incipient motion.

DOI:

Year: 2009