Modeling Effects of Biopolymer Treatment on the Overtopping Performance of an Earthen Embankment

Overtopping is one of the leading causes of failure of dams and levees and is also one of the most difficult to prevent. Overtopping failures occur as water flowing over the crest of an earthen dam or levee erodes the soil and forms a breach. One of the key factors in evaluating the likelihood that an overtopping episode will lead to a breach is the erodibility of the embankment materials. Soil erodibility depends on many factors, including soil fabric, particle size distribution, presence of vegetation, and soil chemistry and mineralogy. Earlier studies have found that chemical treatment can be used to reduce erodibility and therefore slow or even prevent the formation of a breach, but these treatments can have negative environmental impacts. A potential alternative is the use of biopolymer-based treatments to reduce erodibility with an environmentally friendly soil additive, but most biopolymer studies have focused on lab-scale testing or surface erosion, with only a limited number examining longer-term effects of biopolymer treatment on overtopping resistance. This study is part of a larger effort to expand the use of biopolymer-based treatments for overtopping mitigation and focuses on how biopolymer treatment can be incorporated into existing breach modeling software. Effects of biopolymer treatment on key erodibility parameters are reviewed, followed by a discussion of full-scale overtopping tests on a treated and untreated embankment. The breach modeling program WinDAM C is then used to model these experiments, and the results are compared using estimated and best-fit properties. Recommendations for future work are provided.