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PHYSICS OF ROCKS AND PROCESSES
ArticleName Experimental research of explosive jet penetration in rocks
DOI 10.17580/gzh.2016.12.04
ArticleAuthor Kovalevskiy V. N., Argimbaev K. R.
ArticleAuthorData

Saint-Petersburg Mining University, Saint-Petersburg, Russia:

V. N. Kovalevskiy, Associate Professor, Candidate of Engineering Sciences, vladimir_kovalevskiy@mail.ru
K. R. Argimbaev, Assistant, Candidate of Engineering Sciences

Abstract

The article describes an integrated approach to study generation of an explosive jet and its penetration depth in marble and granite under directional destruction with elongated jet charges. It is found that the basic condition of an explosive jet (knife) penetration is that the pressure at the interface exceeds dynamic compressive strength of rocks. The X-ray pattern of the process of the explosive jet penetration in a rock slab is presented together with the data of lab tests on jet penetration depths in case of different focus distances to a rock block. The tests show that penetration rate of an explosive jet in rocks is much less than the explosive jet velocity in air. Also, the penetration rate of an explosive jet lowers as penetration depth grows, and the explosive jet gets longer during penetration. The scheme of interaction between the explosive jet elements and rocks is presented. Based on the test results, the conclusions have been drawn that: deceleration rate of the jet elements is lower in granite than in marble, consequently, the penetration depth value of the explosive jet behaves the same way; the focus distance is higher in granite than in marble; the values of the focus distances are lower than the value of the distance at which an explosive jet is decomposed into elements. The analysis of the laboratory testing result shows that the length of a main crack in the model blocks is greatly influenced by the length of a primary crack: the former is longer with the longer primary crack. Accordingly, generation of long main cracks requires maximized penetration depth of an explosive jet (knife). The data obtained in the research into directional destruction of rocks by long jet charges are recommended for use in actual separation and splitting of stone blocks, in bench design, perimeter control blasting, etc.

keywords Blasting, blasthole, elongated jet charge, rock mass, explosive jet, focus distance, primary crack
References

1. Andrievskiy A. P., Avdeev A. M. Influence of enlarged explosive charge design on explosion funnel parameters. Izvestiya vuzov. Gornyy zhurnal. 2005. No. 4. pp. 112–117.
2. Golovatenko V. D., Golovatenko A. V. Experimental definition of speed of cumulative flow progress through destructable obstacle. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Mashinostroenie. 2014. Vol. 14, No. 3. pp. 5–10.
3. Physics of blast. Third edition, revised and enlarged. Vol. 2. Ed.: L. P. Orlenko. Moscow : Fizmatlit, 2004. 656 p.
4. Rumyantsev B. V., Klimenko V. Yu. Phase transformations in copper cumulative jet during its introduction in silicon carbide. Pisma v zhurnal tekhnicheskoy fiziki. 2011. Vol. 37, No. 21. pp. 87–94.
5. Rumyantsev B. V. Peculiarities of collective introduction of cumulative jets in brittle materials. Zhurnal tekhnicheskoy fiziki. 2015. Vol. 85, No. 4. pp. 138–141.
6. Soldatov V. I., Akimov A. A., Chukov A. N. Experimental and theoretical method of calculation of KS parameters and its formed cavern. Izvestiya Tulskogo gosudarstvennogo universiteta. Tekhnicheskie nauki. 2014. No. 12-1. pp. 254–261.
7. Shekhter B. I., Shushko L. A., Kryskov S. L. Investigation of clamping process for enlarged cumulative charge facing and formation of cumulative knife elements. Fizika goreniya i vzryva. 1977. No. 2. pp. 244–254.
8. Kolpakov V. I., Ladov S. V., Rubtsov A. A. Mathematical modelling of cumulative charge functioning: methodical guidance. Moscow : Bauman Moscow State Technical University, 1998. 33 p.

9. Minin V. F., Minin I. V., Minin O. V. Physics of hypercumulation and combined cumulative charges. Novosibirsk : Siberian Branch RAS, 2013. 275 p.
10. Nefedov M. A., Kovalevskiy V. V, Murakhin A. N. Parameters of influence of enlarged cumulative charges on rocks. Zapiski LGI. 1984. Vol. 99. pp. 72–75.
11. Junqing Huang, Yalong Ma, Kelei Huang, Jianxun Zhao. Analysis of Aperture Shape Changing Trend Base on the Shaped Charge Jet Penetration through the Steel Target. Asia Simulation Conference: proceedings. Part I: Communications in Computer and Information Science, 27–30 October. China : Springer, 2012. pp. 7–12.
12. Savenkov G. G., Barakhtin B. K., Rudometkin K. A. Investigation of structures in copper cumulative jet using the multi-fractal analysis. Zhurnal tekhnicheskoy fiziki. 2015. Vol. 85, No. 1. pp. 98–103.
13. Yang R., Zhang Z., Yang L., Guo Y. Cumulative blasting experiment study of slotted cartridge based on hard-rock rapid driving technology. Chinese Journal of Rock Mechanics and Engineering. 2013. Vol. 32. Iss. 2. P. 317–323.
14. Yan Chang-Bin. Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement. Journal of Central South University of Technology. 2007. Vol. 14, No 2. pp. 230–235.
15. Yingguo Hu, Wenbo Lu, Ming Chen, Peng Yan, Jianhua Yang. Comparison of blast-Induced damage between presplit and smooth blasting of high rock slope. Rock Mechanics and Rock Engineering. 2014. Vol. 47, Iss. 4. pp. 1307–1320.
16. Zhang X., Wu C., Huang F. Penetration of shaped charge jets with tungsten-copper and copper liners at the same explosive-to-liner mass ratio into water. Shock Waves. 2010. Vol. 20, Iss. 3. pp. 263–267.

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