ABSTRACT
Much has been said about ideal detonation and the energy measures associated with attempts to characterise the usefulness of particular explosives in a given rock mass (Cunningham 2002, Sarahan et al. 2006). The theory assumes that the detonation is travelling in one dimension with
1 INTRODUCTION
The blasting community has developed a number of ways of measuring explosive performance. Some are energy based and relate to the chemical energy produced from the reactions of the component chemical within the product. Most explosive companies have ideal detonation codes that factor in the energy lost to the kinetic energy of the shock wave transmission and provide measures of the possible energy available for delivery to the rock. These measures depend on the type of equation of state used and the lower bound pressure cut-off considered. However, in practice, detonations are non-ideal and depend significantly on the type of confinement, the borehole diameter and the way that the constituent chemicals react after the detonation driving zone. Another measure of performance is to invoke the velocity of detonation and to relate this either to ideal detonation code predictions or to unconfined pipe tests experiments. This is often done as a result of the theoretical relationship between velocity of detonation and pressure, surmising that pressure relates to performance. Pressure can now be actually measured in the borehole. Often there is a desire to separate the shock and heave energy components and the pond and Gurney tests have
effectively infinite confinement strength and stiffness and that the reactions are in mechanical, thermal and chemical equilibrium (Byers-Brown and Braithwaite 1993, Braithwaite et al. 1996). Early attempts considered a range of equations of state for the detonation products (Braithwaite et al. 1996) and current versions of the Vixen2009 code use the Williamsburg equation (Braithwaite et al. 2010).Cunningham (2002) has compared a number of explosive adiabats and the pressure volume adiabat for ANFO is shown in Figure 1 for reference.
