The dam break problem for a hyperconcentrated suspension

Abstract

A rheological approach of muddy debris flows is presented for environmental engineering and risk assessment purposes. The debris flow is viewed as a hyperconcentrated suspension of non brownian solid particles. Experimental and theoretical studies are presented versus the concentration. The experimental work generally consists in generating the flow of well characterized suspensions by a dam break. Then, the time evolution of the front as well as that of the stage at given position are accurately determined. On the theoretical framework, the viscous equations of motion of the suspension are written with the shallow water approximation, and the asymptotic solution in a non dimensional form is derived. Finally, the experimental and the theoretical results are successfully compared and the limits of this rheological approach is fixed.