Three dimensional numerical rock damage analysis under blasting load

• We investigate the behaviour of rock mass subjected to blasting load using three-dimensional numerical modelling.
• We take into account four different explosive-rock mass combinations to investigate blast induced damage zones.
• The strain rate has been assumed as the leading criterion for creation of fractures.
• The objective of this study is to recommend a simple blast damage analysis model by using numerical technique.
• This manuscript shows that that blast damage analysis model recommended with this study is successful.

In this study, the behaviour of rock mass subjected to blasting load is investigated using three dimensional finite difference numerical modelling. In the analyses, Mohr-Coulomb failure criterion has been used for the characterisation of the rock mass strength. Stresses acting on the borehole boundary have been simulated by an exponential function which reaches its maximum within a short time and then falls to zero value in a considerable period. The strain rate effect on the mechanical properties of rock material has also been taken into account in the analyses. Different explosive and site conditions have been studied to investigate the effects of loading rate and anisotropic high in situ stresses on blasting performance and blast induced damage zones. Results have shown that the most efficient explosive in rock blasting will be the one with low frequency content but with a sufficiently high borehole wall pressure. In addition, it has been verified that the directions and the magnitudes of major principle stresses affect the development of the crack zone around the borehole. Finally, it has been seen that proposed equation for the dynamic compressive strength of rock material fits very well to general suggestions.