Assessment of the Energy Balance of Rock Masses through Discrete Element Modelling

With the increase of mining depth, rockbursts become one of the most serious hazards in mines. Studies of rockburst mechanisms can be done through the application of various numerical methods at the laboratory and site scales. Among the different methods available, the discrete element method (DEM) is now increasingly used thanks to its capability to explicitly model the initiation and propagation of fractures leading to failure. The paper deals with the evaluation and analysis of the energy components developing inside a rock mass by means of discrete element modeling. For this purpose, the code YADE Open DEM has been used. The rock mass is viewed as an assembly of bonded particles that interact through an elastic-brittle and frictional contact law. Interparticle breakage can occur by either tensile or shear mechanisms and interparticle friction is considered with respect to a Mohr-Coulomb criterion. Pre-existing fractures are explicitly modeled as frictional interfaces. To investigate the evolution of input and dissipated energy, various energy terms are evaluated for different loading paths. The energy terms include boundary works, elastic strain energy, friction and crack dissipation, kinetic energy and damping dissipation. The proposed energetic approach is verified by computing the energy balance of the system during simulations of compression, tension and shear tests.