Numerical modelling of rock fragmentation under high in-situ stresses and short-delay blast loading

Hong, Z; Tao, M; Zhao, M; Zhou, J; Yu, H; Wu, C

Numerical modelling of rock fragmentation under high in-situ stresses and short-delay blast loading

Hong, Z Tao, M Zhao, M Zhou, J Yu, H Wu, C

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Publisher:: Elsevier
Publication Type:: Journal Article
Citation:: Engineering Fracture Mechanics, 2023, 293, pp. 109727
Issue Date:: 2023-12-01

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Field	Value	Language
dc.contributor.author	Hong, Z
dc.contributor.author	Tao, M
dc.contributor.author	Zhao, M
dc.contributor.author	Zhou, J
dc.contributor.author	Yu, H
dc.contributor.author	Wu, C https://orcid.org/0000-0001-8907-8493
dc.date.accessioned	2024-04-08T08:40:54Z
dc.date.available	2024-04-08T08:40:54Z
dc.date.issued	2023-12-01
dc.identifier.citation	Engineering Fracture Mechanics, 2023, 293, pp. 109727
dc.identifier.issn	0013-7944
dc.identifier.uri	http://hdl.handle.net/10453/177578
dc.description.abstract	Since the invention of electronic detonators with a delay accuracy within 1 ms, short-delay blasting technology has been used in mining and tunnelling engineering to improve rock fracturing and control blast-caused vibration. However, the fragmentation characteristics of pre-stressed rock under short-delay blast loading have not been studied in detail. In this study, the interaction between the short-delay blast loading and static in-situ stress is investigated using a FEM-based modelling method and image-processing approach. Firstly, single-hole blasting tests were conducted in an underground roadway with a burial depth of 620 m. Subsequently, a single-hole blasting model was developed in LS-DYNA and validated against one of the experimental results, a two-hole delay blasting model was established to simulate rock fracture and fragmentation under different delay times and in-situ stresses. Finally, the underlying mechanism of in-situ stress affecting the optimum delay time was theoretically analyzed and an analytical solution for optimum delay was proposed. The tested results show that under a borehole length and charge weight of 1 m and 1.5 kg, respectively, the average fragment size is approximately 10.5 cm, and the crater radius and depth are 0.67 m and 0.96 m, respectively. The numerical results indicate that both of average fragment size and fragment size distribution range significantly increase with the increase of in-situ stress, while they first decrease and then increase with the increase of short delay times. Moreover, there is a specific delay window ranging from 0.5 to 3 ms where short-delay blasting improves fragmentation performance, and the optimum delay time increases with the increase of in-situ stress. The findings of this study can aid in improving the efficiency and safety of blasting operations in deep hard rock mining.
dc.language	en
dc.publisher	Elsevier
dc.relation.ispartof	Engineering Fracture Mechanics
dc.relation.isbasedon	10.1016/j.engfracmech.2023.109727
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject.classification	Mechanical Engineering & Transports
dc.subject.classification	40 Engineering
dc.title	Numerical modelling of rock fragmentation under high in-situ stresses and short-delay blast loading
dc.type	Journal Article
utslib.citation.volume	293
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	University of Technology Sydney/Strength - CBI - Centre for Built Infrastructure
utslib.copyright.status	closed_access	*
dc.date.updated	2024-04-08T08:40:52Z
pubs.publication-status	Published
pubs.volume	293

Abstract:

Since the invention of electronic detonators with a delay accuracy within 1 ms, short-delay blasting technology has been used in mining and tunnelling engineering to improve rock fracturing and control blast-caused vibration. However, the fragmentation characteristics of pre-stressed rock under short-delay blast loading have not been studied in detail. In this study, the interaction between the short-delay blast loading and static in-situ stress is investigated using a FEM-based modelling method and image-processing approach. Firstly, single-hole blasting tests were conducted in an underground roadway with a burial depth of 620 m. Subsequently, a single-hole blasting model was developed in LS-DYNA and validated against one of the experimental results, a two-hole delay blasting model was established to simulate rock fracture and fragmentation under different delay times and in-situ stresses. Finally, the underlying mechanism of in-situ stress affecting the optimum delay time was theoretically analyzed and an analytical solution for optimum delay was proposed. The tested results show that under a borehole length and charge weight of 1 m and 1.5 kg, respectively, the average fragment size is approximately 10.5 cm, and the crater radius and depth are 0.67 m and 0.96 m, respectively. The numerical results indicate that both of average fragment size and fragment size distribution range significantly increase with the increase of in-situ stress, while they first decrease and then increase with the increase of short delay times. Moreover, there is a specific delay window ranging from 0.5 to 3 ms where short-delay blasting improves fragmentation performance, and the optimum delay time increases with the increase of in-situ stress. The findings of this study can aid in improving the efficiency and safety of blasting operations in deep hard rock mining.

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http://hdl.handle.net/10453/177578