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Shock and Vibration
Volume 2015 (2015), Article ID 504043, 6 pages
Research Article

Blast-Induced Damage on Millisecond Blasting Model Test with Multicircle Vertical Blastholes

Research Center of Mine Underground Engineering, Ministry of Education, Anhui University of Science and Technology, Huainan, Anhui 232001, China

Received 12 November 2014; Accepted 26 January 2015

Academic Editor: Marcin A. Lutynski

Copyright © 2015 Qin-yong Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


To investigate the blast-induced damage effect on surrounding rock in vertical shaft excavation, 4 kinds of millisecond blasting model tests with three-circle blastholes were designed and carried out with excavation blasting in vertical shaft as the background. The longitudinal wave velocity on the side of concrete model was also measured before and after blasting. Then blast damage factor was then calculated by measuring longitudinal wave velocity before and after blasting. The test results show that the blast-induced damage factor attenuated gradually with the centre of three-circle blastholes as centre. With the threshold value of 0.19 for blast-induced damage factor, blast-induced damage zones for 4 kinds of model tests are described and there is an inverted cone blast-induced damage zone in concrete model. And analyses of cutting effect and blast-induced damage zone indicate that in order to minimize the blast-induced damage effect and ensure the cutting effect the reasonable blasting scheme for three-circle blastholes is the inner two-circle blastholes initiated simultaneously and the outer third circle blastholes initiated in a 25 ms delay.