A Multi-Phase Mass Flow Model

Author(s)
Shiva Prasad Pudasaini, Martin Mergili
Abstract

Geomorphic mass flows are often complex in terms of material composition and its evolution in space and time. The simulation of those hazardous phenomena would strongly benefit from a multi-phase model, considering the motion and-importantly-interaction of phases characterized by different physical aspects including densities, frictions, viscosities, fractions, and their mechanical responses. However, such a genuine multi-phase model is still lacking. Here, we present a first-ever, multi-mechanical, multi-phase mass flow model composed of three different phases: the coarse solid fraction, fine-solid fraction, and viscous fluid. The coarse solid component, called solid, represents boulders, cobbles, gravels, or blocks of ice. Fine-solid represents fine particles and sand, whereas water and very fine particles, including colloids, silt, and clay, constitute the viscous fluid component in the mixture. The involved materials display distinct mechanical responses and dynamic behaviors. Therefore, the solid, fine-solid, and fluid phases are described by Coulomb-plastic, shear- and pressure-dependent plasticity-dominated viscoplastic, and viscosity-dominated viscoplastic rheologies. They are supposed to best represent those materials. The new model is flexible and addresses some long-standing issues of multi-phase mass flows on how to reliably describe the flow dynamics, runout, and deposition morphology of such type of phenomena. With reference to some benchmark simulations, the essence of the model and its applicability are discussed.

Organisation(s)
Department of Geography and Regional Research
External organisation(s)
Rheinische Friedrich-Wilhelms-Universität Bonn, University of Natural Resources and Life Sciences
Journal
Journal of Geophysical Research: Earth Surface
Volume
124
Pages
2920-2942
No. of pages
23
ISSN
2169-9003
DOI
https://doi.org/10.1029/2019JF005204
Publication date
2019
Peer reviewed
Yes
Austrian Fields of Science 2012
105902 Natural hazards, 102009 Computer simulation
Keywords
ASJC Scopus subject areas
Earth-Surface Processes, Geophysics
Portal url
https://ucrisportal.univie.ac.at/en/publications/0be103cc-fe31-4cdf-b961-8f0b1e88a99b