Журналы →  Obogashchenie Rud →  2019 →  №6 →  Назад

Название Crack propagation in rock upon impact
DOI 10.17580/or.2019.06.01
Автор Bolobov V. I., Le-Thanh B., Plaschinsky V. A.
Информация об авторе

St. Petersburg Mining University (St. Petersburg, Russia):

Bolobov V. I., Professor, Doctor of Engineering Sciences, Senior Researcher, boloboff@mail.ru
Plaschinsky A. A., Postgraduate, SlavaPlash@yandex.ru

Vinacomin – Institute of Energy & Mining Mechanical Engineering (IEMM) (Hanoi, Vietnam):

Le-Thanh B., Senior Researcher


Based on the assumption that destruction of a rock fragment upon impact is conditioned upon the achievement by the emerging crack of any of the free surfaces of the fragment, the propagation velocity of a fracture crack vcr was estimated experimentally and by calculation using granite samples of the Vyborg massif. In the experimental setup, impacts at various points on the horizontal surface of granite fragments enabled establishing the most effective impact distance h = leff from the edge of their lateral surface, at which the impact breaks off the largest piece of rock. The dependence of this value on the diameter d of the flat face of the ram tester was established; an analysis of the shapes of the resulting broken-off fragments indicated mutual proximity of the values of their geometric parameters; their dependence on d and the length of the fracture crack lcr were established by calculating the arithmetic mean of these parameters. Such single impact indicators as the rock resistance force Nm, contact stress σc, penetration αp of the ram tester into the rock, and impact duration tm, were calculated; their dependence on d was established. The calculated values of tm were used to calculate the fracture crack propagation velocity vcr. The latter is close to 11 m/s for all granite fragments, regardless of the values of d and tm, which is significantly lower than the values established in other studies. This is due to significant differences in the medium being fractured and in the impact velocity.

Ключевые слова Ram tester penetration, granite fragments, load characteristics, chipped piece parameters, crack propagation velocity
Библиографический список

1. Gorodilov L. V. Experimental investigation of crack formation in rock mass under impact fracture by a hard indenter. Fundamentalnye i Prikladnye Voprosy Gornykh Nauk. 2018. Vol. 5, No. 1. pp. 25–30.
2. Li Sh., Zhao P., Du X., Xiao P. Experimental study on crack evolution characteristics of rock-like materials under different strain rates. Journal of Geophysics and Engineering. 2018. Vol. 15, Iss. 5. pp. 2071–2078.
3. Liu Y., Xu J., Zhou G. Relation between crack propagation and internal damage in sandstone during shear failure. Journal of Geophysics and Engineering. 2018. Vol. 15, Iss. 5. pp. 2104–2109.
4. Wang X., Wu S., Ge H., Sun Y., Zhang Q. The complexity of the fracture network in the failure rock under cyclic loading and its characteristics of acoustic emission monitoring. Journal of Geophysics and Engineering. 2018. Vol. 15, Iss. 5. pp. 2091–2103.
5. Xu J., Zheng Z., Xiao X., Li Z. Crack propagation and coalescence due to dual non-penetrating surface flaws and their effect on the strength of rock-like material. Journal of Geophysics and Engineering. 2018. Vol. 15, Iss. 3. pp. 938–951.
6. Gabov V. V., Zadkov D. A., Nguyen Khac Linh. Features of elementary burst formation during cutting coals and isotropic materials with reference cutting tool of mining machines. Zapiski Gornogo Instituta. 2019. Vol. 236. pp. 153–161.
7. Khalkechev R. K., Khalkechev K. V. Rock disintegration selectivity control based on the methods of similarity and dimensions in the fracture dynamics. Gornyi Zhurnal. 2016. No. 6. pp. 64–66. DOI: 10.17580/gzh.2016.06.04.
8. Lundborg N., Johansson С. H. Experimental determination of the speed of propagation of cracks in glass as a function of the stress. Arkiv for Fysik. 1952. Vol. 4, No. 39. pp. 555–558.
9. Kuzmin Е. А., Pukh V. P. The growth rate of brittle cracks in glass and rosin. Some problems of solid state strength: collection of articles. Мoscow–Leningrad: Publ. House of the USSR Academy of Sciences, 1959. pp. 367–374.

10. Regel V. R. On the kinetics of crack growth in the process of fracture of solids. Zhurnal Tekhnicheskoy Fiziki. 1956. Vol. 26, No. 2. pp. 359–363.
11. Babenkov I. S. Study of interaction of drilling tools and rocks by photoelasticity method. Мoscow: Nedra, 1970. 128 p.
12. Aman S. Microwave based method of monitoring crack formation. Measurement Science and Technology. 2014. Vol. 25, Iss. 5. pp. 1–5.
13. Gaek Yu. V., Drukovannyi М. F., Mishin V. V. On the rate of crack development in rocks and solids and methods of its measurement. Blasting Work. 1963. No. 51/8. pp. 85–96.
14. Danchev P. S., Puchkov Ya. М., Vetluzhskikh V. P. On the propagation speed of cracks in a solid medium during an explosion. Issues of rock destruction by explosion: Proc. of the Institute of Mining, Ural Branch of the USSR Academy of Sciences. Iss. 7. Sverdlovsk: UB of the USSR Academy of Sciences, 1963. pp. 5–13.
15. Lagunov V. А., Mambetov Sh. А. The rate of crack development in rock samples. Prikladnaya Mekhanika i Tekhnicheskaya Fizika. 1965. No. 6. pp. 96–99.
16. Sokolinskiy V. B. Impact destruction machines. Мoscow: Маshinostroenie, 1982. 185 p.
17. Bolobov V. I., Le Thanh Binh. The regularities of the destruction of the projectile material during repeated single strikes. Zapiski Gornogo Instituta. 2018. Vol. 233. pp. 508–512.
18. Zelenin А. N. Fundamentals of soil destruction by mechanical means. Мoscow: Маshinostroenie. 1968. 376 p.
19. Shelkovnikov I. G. Use of impact energy in drilling processes. Мoscow: Nedra, 1977. 160 p.
20. Stavrigin А. N., Tarasov B. G. Experimental physics and mechanics of rocks. St. Petersburg: Nauka, 2001. 343 p.
21. Ushakov L. S., Kotylev Yu. Е., Kravchenko V. А. Hydraulic impact machines. Мoscow: Маshinostroenie, 2000. 416 p.
22. Vaisberg L. A., Kameneva E. E. X-ray computed tomography in the study of physico-mechanical properties of rocks. Gornyi Zhurnal. 2014. No. 9. pp. 85–90.
23. Vaisberg L. A., Kameneva E. E. Interconnection of structural features and physico-mechanical properties of rocks. Gornyi Zhurnal. 2017. No. 9. pp. 53–58. DOI: 10.17580/gzh.2017.09.10.

Language of full-text русский
Полный текст статьи Получить