A comparative study of embankment breach parameters in different breach locations

Abstract

In general, when an embankment breach occurs, the breach expands laterally due to erosion of both breach sides. However, when the breach occurs close to a solid wall, the erosion occurs primarily on one side. This paper presents a study on the comparative parameters of the breaches that occurred at the middle of the embankment width, and at the location adjacent to a solid wall. A physical model is constructed such that the breaches could be observed. The downstream slopes of the embankment model were set at 1:1, 1:1.5, and 1:2. Cohesive soil was used to construct the embankments with the bulk density distributions ranging from 1.4 to 1.7 g/cm3. The experiments were conducted by allowing water to flow over the embankment at different flow rates. The breach dimensions were measured and transformed into dimensionless breach parameters. These dimensionless breach parameters were analysed to ascertain their relation with relevant dimensionless flow parameters. The results reveal that for the same embankment slope and discharge rate, the breach parameters change depending on the location of the breach, except for the parameter of the soil loss volume. The distance between the breach location and the solid wall affects the values of the maximum breach width, the maximum breach depth, and the maximum scour depth. There is shown that breach depth and scour depth for breaches adjacent to the solid wall are deeper than those of the breaches occurring in the middle section of the embankment. In addition to these findings, the empirical relation among these dimensionless breach parameters obtained from other case studies are also discussed.