Discontinuum modelling of blasthole expansion and explosive gas pressurization in jointed media

Recent experimental results indicated that high pressure gases, produced by explosives, play a very significant role in crack development, rock breakage, and subsequent fragmentation and heave. A Discontinuum modelling approach is used in this study to investigate blasthole expansion and gas pressurization. The Discontinious Deformation Analysis (DDA method) is modified to allow for blast modelling and gas pressurization effects. The proposed model for blasthole expansion assumes an adiabatic expansion of gaseous products of detonation and the blasthole chamber is pressurized uniformly. The volume of the blasthole chamber is calculated by the "simplex" theory and is updated at every time step. Variations in pressure upon expansion of blasthole chamber is calculated from an equation of state.