Numerical simulation of real debris-flow events

A one-dimensional model is presented to predict debris-flow runouts. The mo del is based on shallow water type assumptions. The fluid is assumed to be homogeneous and the original bed of the flow domain to be unerodible. The f luid is characterized by a rheology of Bingham type. A numerical tool able to cope with the nature of debris flows has been work ed out. It represents an extension of a second order accurate and conservat ive method of Godunov type. Special care has been devoted to the influence of the source terms and of the geometrical representation of the natural cr oss sections, which play a fundamental role. The application concerns a monitored event in the Dolomites in Italy, where field analyses allowed characterization of the behavior of solid-liquid mi xture as a yield stress material. The comparison between numerical simulati ons and field observations highlights the impossibility of representing all phases of the flow with constant values of the rheological parameters. Nev ertheless the results show that it is possible to separately represent the phase of the flow in the upstream reach and the phase of the deposition in the alluvial fan, with a good agreement with field observations. (C) 2000 E lsevier Science Ltd. All rights reserved.