University of Oulu

Zhang, ZX., Chi, L.Y., Qiao, Y. et al. Fracture Initiation, Gas Ejection, and Strain Waves Measured on Specimen Surfaces in Model Rock Blasting. Rock Mech Rock Eng 54, 647–663 (2021).

Fracture initiation, gas ejection, and strain waves measured on specimen surfaces in model rock blasting

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Author: Zhang, Zong-Xian1; Chi, Li Yuan2; Qiao, Yang1;
Organizations: 1Oulu Mining School, University of Oulu, 90014, Oulu, Finland
2State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100080, China
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 10.1 MB)
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Language: English
Published: Springer Nature, 2021
Publish Date: 2021-04-28


Crack velocity, gas ejection, and stress waves play an important role in determining delay time, designing a blast and understanding the mechanism of rock fragmentation by blasting. In this paper, the emerging times of the earliest cracks and gas ejection on the lateral surfaces of cylindrical granite specimens with a diameter of 240 mm and a length of 300 mm were determined by high-speed photography, and the strain waves measured by an instrument of dynamic strain measurement during model blasting. The results showed that: (1) the measured velocity of gas penetration into the radial cracks was in a range of 196–279 m/s; (2) the measured velocity of a radial crack extending from the blasthole to the specimen surface varied from 489 to 652 m/s; (3) the length of strain waves measured was about 2800 µs, which is approximately 1000 times greater than the detonation time. At about 2850 µs after detonation was initiated, gases were still ejected from the surface cracks, and the specimens still stood at their initial places, although surface cracks had opened widely.

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Series: Rock mechanics and rock engineering
ISSN: 0723-2632
ISSN-E: 1434-453X
ISSN-L: 0723-2632
Volume: 54
Issue: 2
Pages: 647 - 663
DOI: 10.1007/s00603-020-02300-2
Type of Publication: A1 Journal article – refereed
Field of Science: 1171 Geosciences
Funding: This work is financed by K H Renlund Foundation in Finland. The third author is grateful to China Scholarship Council (CSC) for the support of his study. Open access funding provided by University of Oulu including Oulu University Hospital.
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