SLOPE STABILITY METHODS PERFORMANCE IN PREDICTING SCARP FAILURES IN THE ABSENCE OF NOTCHING

The present generation of widely-used dune erosion models (e.g., XBeach, Roelvink et al, 2009) do not explicitly consider geotechnical processes or attempt to model the internal sand-matrix stability of the eroding dune face during storms. However, several previous studies have shown that dunes fail due to a combination of several phenomena including shear, notching, and changing soil saturation (Erikson et al., 2007; Palmsten and Holman, 2010). This paper aims to improve the numerical modelling of shear failures in the absence of notching by including the presence of a phreatic surface and using realistic failure surfaces. Two slope stability methods that are commonly used in the field of geotechnics are tested, called the ‘Ordinary’ and ‘Bishop’ method of slices, respectively. These two so-called ’limit equilibrium’ (LE) methods are evaluated using a subset of the laboratory experimental data reported by Conti et al (2023).