Study on the crack propagation between blastholes under different detonating sequence using finite element method

Detonation methods are significant to the construction efficiency, smoothness of the contour surface and the stability of the rock mass. In this work, based on dynamic finite element method, numerical models for crack initiation and propagation under different detonating sequence types were firstly established. Then parametric analysis was carried out to study the effect of the blasthole spacing and detonation delay time on the crack propagation. Finally, the effect of blasting wave interaction and stress distribution under different detonation sequence types were studied. The results show that the initial and propagation of the directional fracture is dependent on the blasthole spacing and delayed detonation time. The main cracks generated from detonation have the tendency of linear propagation along the concentric line for small spacing. Based on the wave propagation theory, the optimal range of detonation delay time can be calculated. The branch cracks generated and main cracks deviate from the concentric line if the delay time is out of the optimal range.