Abstract
One of the main objectives of all blasting operations is good fragmentation. Rock fragmentation by blasting is a complicated process which involves consecutive loading phases. Additionally the initiation of multiple holes in a blasting operation adds complexity to the process. The intention of this study is to investigate the effect of delay between blastholes in a qualitative manner and in an actual bench scale. The 3D finite difference code (FLAC 3D) was used to model multiple blasthole initiation in a typical bench. The blast loading history was simplified and applied to the blasthole walls. Accordingly, the interaction of explosive energy transferred to rock from each hole was examined as a function of blast-hole delay. A Mohr-Coulomb material model was used for host rock to allow for plastic failure calculations. The conducted numerical study describes the role of delay time in blasting in a qualitative manner. The obtained results show that, at the end of stress wave loading phase, long delays cause the burden to be under a higher stress state and closer to the rock mass failure envelope. In the case of 0 ms delay, in spite of high and fast delivery of energy to the rock mass, the final stress state in the burden is fairly lower than the 7 ms delay case. In other words, in this case, the burden material has a longer stress path to reach the rock mass failure envelope.
| Original language | English |
|---|---|
| Title of host publication | Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 |
| Pages | 363-369 |
| Number of pages | 7 |
| Publication status | Published - Dec 1 2010 |
| Externally published | Yes |
| Event | 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 - Granada, Spain Duration: Sep 13 2009 → Sep 17 2009 |
Publication series
| Name | Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 |
|---|
Conference
| Conference | 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 |
|---|---|
| Country | Spain |
| City | Granada |
| Period | 9/13/09 → 9/17/09 |
Fingerprint
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geotechnical Engineering and Engineering Geology
Cite this
A numerical investigation of the effect of blasthole delay in rock fragmentation. / Mortazavi, A.; Salmi, E. F.
Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9. 2010. p. 363-369 (Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - A numerical investigation of the effect of blasthole delay in rock fragmentation
AU - Mortazavi, A.
AU - Salmi, E. F.
PY - 2010/12/1
Y1 - 2010/12/1
N2 - One of the main objectives of all blasting operations is good fragmentation. Rock fragmentation by blasting is a complicated process which involves consecutive loading phases. Additionally the initiation of multiple holes in a blasting operation adds complexity to the process. The intention of this study is to investigate the effect of delay between blastholes in a qualitative manner and in an actual bench scale. The 3D finite difference code (FLAC 3D) was used to model multiple blasthole initiation in a typical bench. The blast loading history was simplified and applied to the blasthole walls. Accordingly, the interaction of explosive energy transferred to rock from each hole was examined as a function of blast-hole delay. A Mohr-Coulomb material model was used for host rock to allow for plastic failure calculations. The conducted numerical study describes the role of delay time in blasting in a qualitative manner. The obtained results show that, at the end of stress wave loading phase, long delays cause the burden to be under a higher stress state and closer to the rock mass failure envelope. In the case of 0 ms delay, in spite of high and fast delivery of energy to the rock mass, the final stress state in the burden is fairly lower than the 7 ms delay case. In other words, in this case, the burden material has a longer stress path to reach the rock mass failure envelope.
AB - One of the main objectives of all blasting operations is good fragmentation. Rock fragmentation by blasting is a complicated process which involves consecutive loading phases. Additionally the initiation of multiple holes in a blasting operation adds complexity to the process. The intention of this study is to investigate the effect of delay between blastholes in a qualitative manner and in an actual bench scale. The 3D finite difference code (FLAC 3D) was used to model multiple blasthole initiation in a typical bench. The blast loading history was simplified and applied to the blasthole walls. Accordingly, the interaction of explosive energy transferred to rock from each hole was examined as a function of blast-hole delay. A Mohr-Coulomb material model was used for host rock to allow for plastic failure calculations. The conducted numerical study describes the role of delay time in blasting in a qualitative manner. The obtained results show that, at the end of stress wave loading phase, long delays cause the burden to be under a higher stress state and closer to the rock mass failure envelope. In the case of 0 ms delay, in spite of high and fast delivery of energy to the rock mass, the final stress state in the burden is fairly lower than the 7 ms delay case. In other words, in this case, the burden material has a longer stress path to reach the rock mass failure envelope.
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UR - http://www.scopus.com/inward/citedby.url?scp=84859812607&partnerID=8YFLogxK
M3 - Conference contribution
SN - 9780415482967
T3 - Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9
SP - 363
EP - 369
BT - Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9
ER -