Rock blasting is one of the most commonly used technique in open-pit mining in terms of economic and efficiency. This technique, however, can cause serious accidents or environmental impacts such as flyrock, ground vibration or noise. In order to control such negative impacts, rock fracture mechanism induced by blasting should be theoretically considered. For this reason, small-scale blasting test with mortar block was performed in this research. Strain profile of the surface on the mortar block was analyzed by means of digital image correlation (DIC) method based on a series of photographs taken by two high speed cameras. According to the results, the value of both lateral and longitudinal strain gradually increased from approximately 50 μs after the detonation which is the arrival time of S-wave from the blasting sources; therefore, it can be said dynamic strain can be assessed by DIC. As a next step, strain rate was calculated for further discussions. The results show that strain rate strongly influence on crack generation and crack growth.
blasting, surface mining, scaled experiment, digital image correlation