Experimental results of blast-induced cracking fractal characteristics and propagation behavior in deep rock mass

Herein, static stress is used to simulate high in-situ stress in a deep rock mass. The effect of this stress on the fractal characteristics and propagation behavior of blast-induced cracking are analyzed using a laboratory model experimental method combined with fractal theory, a dynamic caustics method and high-speed camera technology. The results show that the static stress increases the fractal dimension of the blast-induced crack and the degree of damage to the medium. Static stress also has a guiding effect on the blast-induced crack propagation, causing the distribution of the blast-induced crack to be more complicated. Under the combined action of static stress and blasting stress, the fractal characteristics of the blast-induced cracking in different ranges of the fracture zone exhibit significant differences. Larger static stress increases the stress concentration at the tip of the blast-induced crack, allowing the blast-induced crack to propagate at a higher velocity in the direction of the static stress and form a longer length.