关键词: 预裂爆破, 裂缝扩展速度, 爆生气体扩散速度, 预裂孔间距, 动态强度

Abstract: The pre-split crack initiation mechanism during the pre-split blasting is still a controversial topic. The clarification of the crack initiation mechanism during the pre-split blasting is of great significance for the engineering design. Comparative analysis indicates that the crack propagation velocity and the blasting-induced gas dissipation velocity change under different decoupling charging coefficients. The comparison of the magnitude of the two velocities shows that the crack propagation is caused by both the blasting stress wave and blasting-induced gas dissipation. It is thus concluded that the pre-split blasting mechanism is characterized by a dynamic process depending on the time and charging parameters. According to the blasting stress wave and blasting-induced gas dissipation induced stress distribution of the hole surrounding, a design method of the pre-split blasting hole space and a calculation equation based on the dynamic compressive and tensile strengths of the rockmass are proposed.