A Soil Tensile Strength Based Headcut Migration Model of Breach Side Slope

Abstract

The headcut migration describes the physical process of breach side slope retreat that governs the widening of the breach. Modeling the growth of a breach due to embankment failure is the first step in mapping the resulting inundation in a floodplain. As removal of soil from the toe of the headcut effectively removes physical support for the upper part, the headcut fails on the plane normal to the direction of tensile stress. This process is a typical mode of tensile failure. A numerical model of the headcut migration was established by integrating the effects of the soil tensile strength, soil permeability and embankment geotechnical characteristics. Thus, a simple analytical equation was finally obtained to predict the critical length of the headcut. Furthermore, the presented model was verified by using the limit equilibrium method (LEM) for three typical embankment scales (2, 4 and 6 m high). The comparisons between the present model and the LEM show good agreements. The present model could provide a simple method to predict the critical length of the headcut migration and easily be adopted to breach widening models.

Keywords

• headcut migration
• soil tensile strength
• numerical model
• breach
• limit equilibrium method