A model for the runout analysis of rapid flow slides, debris flows, and avalanches

Runout analyses are used for risk assessment and design of remedial measures against rapid landslides such as debris flows, debris avalanches, rockslide avalanches, large-scale liquefaction failures, and slides of fill and mining waste. A continuum model has been developed to simulate the characteristics of these phenomena. The model is based on a Lagrangian solution of the equations of motion and allows the selection of a variety of material rheologies, which can vary along the slide path or within the slide mass. It also allows for the internal rigidity of relatively coherent slide debris moving on a thin liquefied basal layer. The effects of lateral confinement are accounted for in a simplified manner. The model is shown to compare favourably with results of controlled laboratory experiments and other analytical tools for several different materials and problem configurations. Examples of the practical use of the model to predict the runout of coal mine waste flow slides and flows of liquefied granular tailings are presented. Key words : landslides, dynamic analysis, runout prediction, debris flows, debris avalanches, flow slides.