Effects of Heterogeneity and Fracture Toughness on Rock Spalling investigated by Particle Flow Code (PFC) - Subspring Network Voronoi (SNBV) Model

ABSTRACT: This work investigates the effect of fracture toughness on rock spalling based on homogeneous and heterogeneous materials using the Particle Flow code (PFC) -Subspring Network Breakable Voronoi (SNBV) model. The PFC-SNBV model implements more realistic fracturing mechanisms with simple input parameters and calibration. For verification in laboratory scale, Lac du Bonnet granite from the Mine-by Experiment in Canada was adopted and several tension tests were conducted to estimate the fracture toughness of homogeneous and heterogeneous models. Subsequently, the Mine-by Experiment was implemented by PFC-SNBV for in-situ scale validation. The results of both laboratory and in-situ scale application indicate that PFC-SNBV model effectively implements fracture mechanisms for the homogeneous model. On the other hand, the fracture toughness of heterogeneous model was overestimated and exhibited large variance resulting in the performance of rock spalling prediction. This work highlights the importance of properly considering fracture toughness in the fracture mechanisms of the heterogeneous model within the PFC-SNBV.