Flow and deposition of muds and debris

Abstract

In this paper, a study of debris flow under dispersive conditions is presented. Evidence shows that debris flow is composed of a mixture of water and of all-sizes sediments. Characteristics of the debris flow deposition process are considered. The debris fan is formed when the channel slope decreases or the channel width suddenly increases. Rheologic flow functions are presented and the different types of shear stresses are given. Two different theories to explain the buoyant forces on solid particles, in a two-phase medium of smaller density, are discussed. Conservation of mass and conservation of volume equations as well as the conservation of momentum equations in both x and y directions are analyzed. Results of numerical simulations to predict simultaneously the velocity distributions and the shape of the debris-deposit area, are given. Results by Takahashi (1991) and Quisca (1995) methodologies are contrasted, in dimensionless form, respect to experimental laboratory data. It is found that numerical approaches are reasonably close to experimental laboratory data, which represent two different flow conditions: that of saturated sand flow and the flow of water and small plastic cylinders at different concentrations.