High-Speed Image Analysis of the Rock Fracture Process under the Impact of Blasting

Abstract

The purpose of this paper was to observe the generation, development, and extent impact of rock fissures under the blasting process; the failure process of rock under the gases expansion pressure. The latest high-speed camera, producing about 30,000 frames per second (each grid was 32 µs, and exposure time 4 µs), was used to capture the failure process of rock in blasting concrete specimens. The types of cracks and the rate of extended development in a quantitative way were recorded for observation, analysis, and verification of the failure mechanism of induced by blasting. The results showed that the gas expansion rate after blasting reached the maximum of about 200 µs and then gradually attenuated. As to the development rate of the fragmentation of rock after blasting, it reached the maximum of about 130 µs, and the attenuation then became gradual. It is concluded that high-speed photography provides meaningful scientific basis for study of the detonation theory of explosives, rock blasting fracture mechanism, analysis of blast effects, etc. Further improvement and research can be done on the control of the synchronous operation of blasting and photography, and the three-dimensional spatial analysis of the rock blasting process.