FLUID DYNAMIC TREATMENT OF THIXOTROPIC DEBRIS FLOWS AND AVALANCHES

Some forms of mud flows and debris flows exhibit a non-Newtonian thixotropic behaviour, and this study describes a basic study of dam break wave with thixotropic fluid. Theoretical considerations were developed based upon a kinematic wave approximation of the Saint-Venant equations down a prismatic sloping channel and combined with the thixotropic rheological model of Coussot et al. (2002). The analytical solution of basic flow motion and rheology equations predicts three basic flow regimes depending upon the fluid properties and flow conditions, including the initial degree of jamming of the fluid. The present work is the first theoretical analysis combining successfully the basic principles of unsteady flow motion with a thixotropic fluid model, which was verified with systematic laboratory experiments