Study on the crack propagation behaviour of eccentric uncoupled blasting in a deep-level rock mass

ABSTRACT To explore the dynamic crack propagation behaviour in the fracture zone and the damage characteristics of the rock mass around the blasthole during eccentric uncoupled blasting of a deep-level rock mass, theoretical analysis, model experiments and numerical simulation studies have been described in this paper. Firstly, the stress state of the crack and the stress distribution state and failure mechanism of the rock mass around the blasthole under the influence of the in-situ stress, and the pressure distribution of blast shock wave on the blasthole were analysed. Secondly, with the help of a new digital laser caustics experimental system, the eccentric uncoupled blasting model experiment under the action of the in-situ stress was carried out. The fractal damage theory is used to quantitatively evaluate the damage degree of the rock mass in different areas around the blasthole, and the blast-induced crack propagation mechanical behaviour characteristics in the fracture zone are analyzed from the perspective of dynamics. Then, based on the LS-DYNA software, a numerical simulation study was conducted on the eccentric blasting of deep rock mass. Finally, some discussions and suggestions are provided for the analysis of blasting mechanisms in a deep-level rock mass.