Author(s): Yonghui Zhu; P. J. Visser; J. K. Vrijling
Linked Author(s): Yonghui Zhu
Keywords: Model; Headcut; Migration rate; Prediction; Jet impingement; Scour hole
Abstract: A headcut is a vertical or near vertical drop in elevation occurring in rill, gully, earth spillway or overtopped embankment, etc. where intense local scour takes place. The rate of headcut migration is of great interest for soil erosion, sediment yield, landscape evolution, earth spillway safety and embankment overtopping erosion, etc. However, prediction of the headcut migration is a very complicated issue and far from mature. In this paper an analytical model for the prediction of headcut migration is developed. The model is composed of three main components: trajectory of the impinging jet; jet scour in the bed downstream; and headcut undercutting and slope instability. The influence of seepage on the headcut migration has been taken into account. Based on the input data, e. g. characteristics of the approaching flow on the headcut top, height of the headcut, and properties of the soil, the scour hole development and headcut migration can be predicted by the model. The model was applied to calculate the headcut migration of experiments performed by Bennett et al. (2000). Good agreements were achieved between the model calculated headcut migration rates and those measured in the experiments.
Year: 2004