Numerical and experimental modeling of mudflows

Details

Supervisors

Rattez, Hadrien ; Soares Frazao, Sandra

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil des constructions, à finalité spécialisée

Abstract

Current trends and future projections for natural disasters reinforce the need to develop forecasting tools. Against this backdrop, the current Master's thesis focuses on developing a simulation model for mudflows, destructive events which occur in mountainous regions. This document outlines the theoretical approach that enabled the construction of an initial mudflow calculation module in the Watlab program. The program, developed by the hydraulic research team at UCLouvain, solves the Shallow Water Equations with a Finite Volume Method. The aim of this thesis was to add an initial calculation function for these very specific and complex flows. In order to develop such a module, this work first focused on a theoretical synthesis of the behaviors and main mechanisms encountered with mudflows. The model therefore incorporates these concepts or responds to the behaviors that are predicted. The model is then developed by modifying the friction formulation of the classical Shallow Water Equation system. A single-phase assumption made possible the derivation of the mathematical expressions to be inserted into Watlab. Some formulations were proposed to express Bingham rheology and Herschel-Bulkley rheology as friction source terms inside the Shallow Water Equations. Also, the numerical difficulty of treating the stopping ability of the material with a Finite Volume scheme is exposed along with the solution strategy that has been implemented. Finally, the model was tested in a controlled laboratory environment using data provided by Politecnico di Milano, and then on a large scale: the devastating flow of rocks, ice, and soil that destroyed the village of Blatten in late spring 2025. The model has been found to have some weaknesses, but the consistency between observations and actual measurements reinforces its potential if future improvements are expected for the Watlab mudflow calculation module.