COMPUTATION OF A MUD FLOW PROPAGATION FOR PREDICTIVE PURPOSES

摘要

Debris flow and mud flow disasters have been recognized as a critical problem that may cause loss of life and severe destruction of property. At present, the formation process and the propagation of these phenomena are the object of continuing research. Although these aspects need further studies, a practical tool for predictive purpose is required. When the characteristics of the debris flow are similar to those of a continuous fluid, a system of momentum and mass conservation equations for gradually varied fluid flow may be applicable to simulate the propagation. Different resistance modelling techniques are available, which require the proper estimation of parameters for describing the mud/debris flow characteristics. The difficulties and uncertainties in determining these parameters in many situations promote the use of a simple technique based on Manning's equation. In the present work, a first order numerical scheme is implemented to integrate the one-dimensional De St. Venant equations. A series of tests is carried out for the Stava Valley mud flow (Italy, 1985) and the numerical results are compared with measured and estimated values (Takahashi, 1991). The influence of the Manning roughness coefficient, cross-section shape and initial condition on the quantities that most interest engineers in practice are analysed.