Using a particle hybrid method to model coastal bluff collapse during extreme events

This paper investigates the concept of modeling cliff stability and collapse during extreme erosion events using a hybrid model method combining Weakly Compresible Smoothed Particle Hydrodynamics (WCSPH) with a particle based geotechnical stability module (GeoSPH). The WCSPH model has been developed to include a sediment transport and morphological model to predict erosion of a beach slope under a wave climate. The GeoSPH model is based on a displacement stepping method and due to its particle nature it sidesteps the mesh straining and distortion that hinders many traditional models. The model concept and future research direction is investigated and the initial results of erosion and collapse in a storm event are presented. Conventional methods of bluff collapse are often probabilistic, based on extrapolation bluff retreat rates, or reliant on an equilibrium profile, and as such struggle to adapt the predicted movement when changes occur to either the bluff or to the wave climate. Using a hybrid model of wave-driven erosion and bluff stability allows for site by site analysis and can be run without any data of past events.