Thesis supervisor: Majid Movahedi Rad
Location of studies (in Hungarian): Széchenyi István University Abbreviation of location of studies: SZE
Description of the research topic:
A deeper understanding of the mechanical properties of granular materials is of great importance for the accurate prediction of the behaviour of geotechnical structures, for improving safety planning and risk assessment capability. The mechanical behaviour of granular materials is rather complex and the incremental stiffness mainly depends on the morphology of the material, the current stress state, packing density, solid hardness, inter-granular friction angle and the direction of the deformation path. Under stress levels where grain crushing becomes significant the initial grain size distribution changes and a reduction of the void space caused by a reorientation of particles in the grain skeleton takes place. The aim of the proposed research is the refined modelling of the influence of grain crushing on the mechanical behaviour of dry and cohesionless granular materials such as sand, gravel and broken rock. The amount of grain crushing is not only a question of the pressure level, but also influenced by the loading path and micro-structure effects. Particular attention will be paid to the behaviour of stress paths related to proportional strain paths, which, in general, is substantial for the calibration and the evaluation of the performance of numerical models. To study the course of the stress paths and the evolution of grain crushing for different strain path directions the discrete element method (DEM) will be used with respect to crushable and arbitrarily shaped agglomerates.
For application, programming skill and good knowledge of geomechanics are required.