Numerical analysis of blast-induced damage in rock slopes

Blast-induced disturbance is one of the major risks in rock engineering. Hoek et al . considered the disturbance factor (D) in the Hoek–Brown failure criterion. The lack of a detailed guide has led to technical challenges so that Hoek proposed numerical modeling to solve this problem. In this study, numerical modeling of a simple slope through 3D Distinct Element Code (3DEC) was carried out considering two modes of discontinuities to update and quantify the simple descriptive guide. Each of these modes was divided to 5 models based on rock mass properties, and then, the relevant borehole pressure was applied. Blast-induced dynamic changes were qualitatively analyzed using the failure zone capabilities in 3DEC analysis. The results were then quantitatively analyzed with the assist of Fish programming language using the recorded peak particle velocities values. The impact of an increase in burden and spacing on dynamic changes was investigated. According to qualitative analysis, discontinuities reduce the dynamic pressure; geological strength index (GSI) is related to the expansion of damage; and direction of discontinuities is effective in transferring the dynamic pressure. A coefficient of determination of 0.922 was obtained in quantitative analysis. Furthermore, the distance from the blasting site, dip of the discontinuities, GSI and the factor D had the highest impact on the rock mass damage, respectively. Based on the effect of the direction of discontinuities, type of rock mass, burden and spacing on the factor D, the previous estimation guide was updated.