The effect of grain interlocking in discrete element modelling of rock cutting

In this study, actual laboratory rock cutting tests on sandstone specimens that were performed at NTUA's Laboratory of Excavation Engineering were simulated numerically with the use of a 3D bonded particle DEM model implemented in Yade. The numerical assembly was calibrated to closely match the macroscopic strength, Young's modulus, and brittleness of the real material, by controlling the grain interlocking through careful selection of the appropriate value for the interaction range coefficient. The calibrated model was then used to examine the effect of the microparameters' values on the cutting force history and the failure mechanism. The Fast Fourier Transformation was used to compare the characteristics of the simulated cutting force data with those from the actual cutting tests. It was found that for high values of the interaction range coefficient the numerical model showed a more brittle behaviour, while for low values the simulation behaved more realistically for the specific type of rock. It is concluded that the use of the interaction range coefficient can substantially provide more realistic simulations of the cutting process by capturing both the rock-cutting tool interaction and the failure mechanism.