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Grainsize effects on the crushing behavior of unsaturated granular solids
Granular solids interacting with underground technologies are often subjected to high pressures. Such conditions involve alterations of their microstructural features, which are invariably coupled with changes in moisture content and capillary pressure. In this contribution we use a reformulation of the Breakage Mechanics theory to model comminution in wet granular assemblies [Buscarnera and Einav, 2012]. By using a dataset for sands, we quantify the relation between a geometric descriptor of the assembly (i.e., the mean grainsize) and the constants that control the suction air-entry value and the stress threshold at the onset of particle crushing [Zhang and Buscarnera, 2014]. Analytical expressions are obtained to describe the dependence of the water retention properties of crushed sands on the degree of breakage, as well as to relate the magnitude of the yielding pressure with grainsize characteristics. Comparisons against data are discussed, showing that the analytical findings provide a theoretical basis to infer the relation between micro-scale attributes widely used for soil/rock characterization (e.g., the grain size distribution) and standard continuum properties for engineering analyses (e.g., the yield stress at the onset of crushing and the suction air-entry value of a granular system).Author(s):
Giuseppe Buscarnera
Northwestern University
United States
Yida Zhang
Northwestern University
United States