Micro-mechanical modelling of unsaturated packings using CFD-DEM and computed tomography (MIME-UP)
May 1, 2022
April 30, 2024
The main objective of the proposed project is to investigate the influence of capillary effects in partially saturated sands on their mechanical and hydraulic behaviour. Therefore, numerical simulations as well as micro-scale experiments in an x-ray tomograph are planned. For the numerical simulation of partially saturated sands, the resolved CFD-DEM will be used. The existing method will be supplemented by a two-phase flow formulation to consider the influence of pore water and pore air. The micro-scale experiments performed in the x-ray tomograph will be used to validate the newly developed models. Special attention is thereby paid to the formation of capillary bridges during desaturation of a sand column as well as the deformation behaviour and load-response in a triaxial test. For this purpose, the computation of the interaction between particles, fluid and a deforming, load-responsive membrane will be developed in the framework of resolved CFD-DEM. In a possible extension of two years, unsaturated triaxial tests will be conducted in the CT-tomograph to understand the hydro-mechanical behaviour of sand. The developed tools of the first funding period will be combined and extended to model unsaturated triaxial tests.To reach the defined objectives a co-operation between Hamburg University of Technology/Germany and DCS Computing Linz/Austria is planned. DCS is developing the code CFDEMÒcoupling, which is used in the research project. This cooperation is covered by the D-A-CH agreement (DFG in Germany and FWF in Austria).