Fractal evolution characteristics of fracture meso-damage in uniaxial compression rock masses using bonded block model

Abstract

In the realm of underground mining engineering, an investigation into the failure mode of deep fractured rock masses and their corresponding acoustic emission signal characteristics is conducted via uniaxial compression tests. Subsequently, a fractal damage renormalization group mechanical model is formulated to elucidate the behavior of such fractured rock masses. Employing the BBM numerical simulation method, the fracture process of synthetic rock samples is analyzed, thereby confirming the efficacy of the aforementioned mechanical model. The numerical simulations underscore that the expansion of fractures fundamentally underpins the deterioration of rock mass strength. A decrease in peak load correlates with an increase in fracture fractal dimension, resulting in a 14.2% reduction in compressive strength alongside an approximate 8.7% rise in average fracture fractal dimension. Comparison between tetrahedral and Voronoi block synthetic rock samples reveals the former's superior aptitude in depicting the fracture behavior of fractured rock masses, particularly in terms of simulating acoustic emission characteristics and failure modes. Moreover, the variation in fracture fractal dimension with the hole defect's position is observed, with its maximum value aligning with the vertical hole defect axis. This observation underscores the potential utility of visually monitoring deep rock fracture dynamics as a foundational element for quantitatively evaluating fracture damage and strength degradation in deep rock formations.