A MULTIPHASE COMPUTATIONAL FRAMEWORK AND ITS APPLICATIONS TO STUDY THE BEHAVIOUR OF SILTY SANDS

This thesis introduces a new numerical tool combining the advantages of discrete and continuum modelling approaches to provide quantitative descriptions on the interaction of different phases in silty sands (i.e. water, fines and coarse phases). With this new approach, both fluid and fines particles are treated as continuous phases, while coarse sand particles are still treated as a discontinuous phase to maintain the discrete feature of geomaterials. The main outcomes of this study include i) the comprehensive DEM study on the effect of fines on the behaviour of silty sands, ii) the development of a new continuum approach with a two-phase Eulerian-Eulerian CFD model to upscale fine granular material from discrete to continuum phase, and iii) the development of a three-phase CFD-DEM coupling framework for detail descriptions silty sands at a satisfactory level.