Processes of initial stage of expansions of explosive cavity in blasthole charge

Kurinnyi, V. P.; Garkusha, I. P.; Nikiforova, V. O.

Purpose. Research into processes that occur in the blasthole and rock during the first 300 <$Emu>s after a detonation wave passing the given blasthole cross-section and determine the effectiveness of rock fracture. Methodology. The analytical method of research based on fundamental positions of solid medium mechanics was applied. Findings. The mechanisms of rock fracture in fine-dispersed crushing zone were considered. The valuation of dependences versus time of the blasthole radius increase, the displacement velocity of blasthole walls and of the detonation products pressure changing during the first 300 <$Emu>s after the explosion, was fulfilled. It is shown that the pressure in fine-dispersed crushed zone decreases exponentially and is inversely proportional to the square root of the distance to the blasthole axis. Originality. It was found that the main mechanism in the fine-dispersed destruction zone is instantaneous rock destruction by shear stress. The particles size, into which the rock breaks down, is directly proportional to the width of chemical reaction zone in the explosive. Dependencies of explosion cavity radius, rock fracture velocity at the contact with detonation products and detonation products pressure on time are estimated using the adiabatic equation for detonation products with a constant index, taking into account that a strong compression wave is formed in the rock. It is shown that pressure decreases exponentially from the distance to the borehole axis in the fine-dispersed destruction zone. Practical value. The result of this work makes it possible to develop explosives with small fine-dispersed destruction zone and substantiate charges parameters with inert and water interval, thus reducing the size of a finedispersed destruction zone.


	Наукова періодика України		Naukovyi visnyk Natsionalnoho Hirnychoho Universytetu