• Explosives and Blasting
• /
• v.29 no.1
• /
• pp.1-9
• /
• 2011

Air deck charge blasting method which has been generally used in a surface mine and large scale developing site is one of the improved techniques with blasting effectiveness. Many studies and experiments have been tried to investigate the characteristics of pressure distribution in a blasting hole and increase the effectiveness of air deck charge blasting method. In this study, changes of pressure occurred in sections of air deck installed in various ways was computed and also changes of pressure with the location and length of air deck was analyzed, using numerical analysis program. Basically, all the numerical analysis was 2-Dimensional analysis and equation of status of explosives was JWL-EOS. Only to evaluate the variations of pressure in blast hole, it was assumed that rock mass is homogeneous but rock mass has different density and intensity.

• Explosives and Blasting
• /
• v.36 no.4
• /
• pp.1-8
• /
• 2018

This numerical study was intended to evaluate the applicability of the half charge blasting to mining and tunnelling. The half charge blasting is a method that two separate rounds are sequentially blasted for the rock burdens in which long blast holes have already been drilled at one operation. The aim of the method is to decrease the construction cost and period in mining and tunnelling projects as well as to increase the blasting efficiency. Several numerical analyses were conducted by using the Euler-Lagrange solver on ANSYS AUTODYN to identify the effects of the suggested method on the blasting results in underground excavations. The overall performance of the suggested method was also compared to an ordinary blasting method. The analysis model was comprised of the Eulerian parts (explosive, air, and stemming materials) and the Lagrangian parts (rock material). As a result, it was found that, owing to the air decks formed in the bottom parts of the long blast holes, the first round of the suggested method presented a higher shock pressure and particle velocities in the vicinity of the blast holes compared to the ordinary blasting method.