ABSTRACT
In the present paper, the rock mineral structure is described as a Voronoi diagram where the Voronoi cells are polygonal finite elements. The minerals constituting the rock are represented by random clusters of polygonal finite elements. Rock fracture is described in the continuum sense by using a damage-viscoplasticity model based on the Hoek-Brown criterion. Due to the asymmetry of the tension and compression behavior of rocks, separate scalar damage variables, driven by viscoplastic strain, are employed in tension and compression. The equations of motion are solved by explicit time marching since the final aim of this research project is to model transient problems with contact loading (such as percussive rock drilling). In the numerical examples, the capabilities of the present numerical approach are demonstrated. Specifically, uniaxial tension and compression tests of a numerical rock sample are simulated under plane strain conditions. It is shown that the present method can capture the salient features, including the stress-strain response and the failure modes, of typical rock behavior in these constitutive tests.
