Fractal Behavior of Size Distribution and Specific Surface Area of Blasting Fragments

The shape characteristics of blasting fragments are important for analyzing the blasting fragmentation mechanism and evaluating the fragmentation energy efficiency. In this study, through field blasting experiments and morphological parameter measurements, fractal theory was employed to reveal the fractal characteristics of rock blasting fragmentation. Using the fragmentation fractal dimension, the probability of rock blasting fragmentation was analyzed, and a predictive formula for the specific surface area (SSA) of blasting fragments was established. For fragments, the fractal dimensions of the particle size distribution calculated using different characteristic sizes were less than 2.0. When the fragment size distribution had dual fractal characteristics, significant differences were observed in the scale-free interval and fragmentation fractal dimension. Within the large scale-free interval, the fragmentation fractal dimension was mostly greater than 2.3, whereas within the small scale-free interval, it tended to be less than 2.0. The rock fragmentation process typically consisted of two or three breakage levels, with a similarity ratio of 0.5 and an average fragmentation probability ranging from 0.44 to 0.71. The predicted SSA of the blasting fragments closely matched the measured values. The findings provide valuable insights into the mechanism of rock blasting fragmentation and the calculation of fragmentation energy consumption.