Three dimensional discrete element modelling of soils

The Discrete Element Method (DEM) is a powerful numerical tool for studying the large deformations, local yield, and bifurcation-type behaviour that is typical of cohesionless granular soils. Considerable experience has been gained in the Geotechnical Section of the Department of Civil Engineering at the University of Toronto in the modelling of soil behaviour using a two dimensional disc-based DEM program named DISC. With this knowledge it was decided to develop a three dimensional DEM program and compare its usefulness to that of DISC.; This report describes the development and testing of the three dimensional DEM program SPHERES. Program SPHERES is able to model the general behaviour of dry cohesionless granular assemblages of particles. However it is not able to quantitatively model real soils. This is a common shortcoming of many DEM programs, as many simplifying assumptions are required.; A limited comparison of SPHERES and DISC shows that SPHERES exhibits somewhat superior results in terms of modelling the strength properties of soils. Overall, however, the restrictions that were required in SPHERES in order to model in three dimensions severely restrict its usefulness. DISC appears to be more flexible and is recommended for future research.