Strain Field Development, Fracturing, and Gas Ejection in Decoupled Charge Blasting Using Granite Cylinders
Chi, Li Yuan; Xu, Xuan; Zhang, Zong Xian; Yang, Jun (2024-08-02)
Springer
02.08.2024
Chi, L.Y., Xu, X., Zhang, ZX. et al. Strain Field Development, Fracturing, and Gas Ejection in Decoupled Charge Blasting Using Granite Cylinders. Rock Mech Rock Eng 57, 10133–10151 (2024). https://doi.org/10.1007/s00603-024-04079-y
https://creativecommons.org/licenses/by/4.0/
© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
https://creativecommons.org/licenses/by/4.0/
© The Author(s) 2024. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
https://creativecommons.org/licenses/by/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202408145400
https://urn.fi/URN:NBN:fi:oulu-202408145400
Tiivistelmä
Abstract
This study explored the fracture process of granite cylinders with a centric charge, varying decoupling ratios by conducting laboratory-scale experiments and numerical simulations. In experiments, the three-dimensional (3D) digital image correlation (DIC) technique was employed, using frames captured by two synchronized high-speed cameras. This instrumentation permitted the observation of full-field strain variation, the development of fractures, and gaseous products escaping from the cylinders’ surfaces. Granite cylinders measuring 240 mm in diameter and 300 mm in length served as specimens in blasting experiments, and each specimen had a charge of approximately 3 g. Specimens had a centric blasthole with a diameter of either 10 mm, 14 mm, or 20 mm. The corresponding decoupling ratio varied from 1.8 to 3.6, and the gap between the charge and the blasthole wall was filled with water or air. The experimental results showed that: (1) specimens with decoupling ratios of 1.9 and 2.6 exhibited initial strains on the cylindrical surface between 20 μs and 40 μs. (2) Specimens with water-filled blastholes developed fractures faster and in a denser manner compared to those with air-filled blastholes. In addition, fractures resulting from air-filled blastholes appeared smoother than those from water-filled blastholes. (3) The gas ejection time for the air-filled blasthole remained basically consistent across decoupling ratios ranging from 1.5 to 3.61, varying between 400 μs and 520 μs. The utilization of water-filled blastholes effectively minimized the escape of gaseous products from the cylindrical surface. Numerical simulation conducted with LS-DYNA exhibited results that aligned well with the observed fracture patterns in the experiments. This study aims to provide a better understanding of the fundamental mechanisms of rock behaviors in decoupled charge blasting.
This study explored the fracture process of granite cylinders with a centric charge, varying decoupling ratios by conducting laboratory-scale experiments and numerical simulations. In experiments, the three-dimensional (3D) digital image correlation (DIC) technique was employed, using frames captured by two synchronized high-speed cameras. This instrumentation permitted the observation of full-field strain variation, the development of fractures, and gaseous products escaping from the cylinders’ surfaces. Granite cylinders measuring 240 mm in diameter and 300 mm in length served as specimens in blasting experiments, and each specimen had a charge of approximately 3 g. Specimens had a centric blasthole with a diameter of either 10 mm, 14 mm, or 20 mm. The corresponding decoupling ratio varied from 1.8 to 3.6, and the gap between the charge and the blasthole wall was filled with water or air. The experimental results showed that: (1) specimens with decoupling ratios of 1.9 and 2.6 exhibited initial strains on the cylindrical surface between 20 μs and 40 μs. (2) Specimens with water-filled blastholes developed fractures faster and in a denser manner compared to those with air-filled blastholes. In addition, fractures resulting from air-filled blastholes appeared smoother than those from water-filled blastholes. (3) The gas ejection time for the air-filled blasthole remained basically consistent across decoupling ratios ranging from 1.5 to 3.61, varying between 400 μs and 520 μs. The utilization of water-filled blastholes effectively minimized the escape of gaseous products from the cylindrical surface. Numerical simulation conducted with LS-DYNA exhibited results that aligned well with the observed fracture patterns in the experiments. This study aims to provide a better understanding of the fundamental mechanisms of rock behaviors in decoupled charge blasting.
Kokoelmat
- Avoin saatavuus [38841]
Ellei muuten mainita, aineiston lisenssi on https://creativecommons.org/licenses/by/4.0/