Assessment of the loading rate impact on the uniaxial compressive strength of hard rocks and their failure behavior

A.A. Kozyrev, N.N. Kuznecov, A.K. Pak
Mining Institute Kola Science Centre of the Russian Academy of Sciences, Apatity, Russian Federation
Russian Mining Industry №1 / 2024 стр. 126-131

Abstract: When studying physical and mechanical properties of rocks, one of the main parameters to be determined is their uniaxial compressive strength. During laboratory experiments, the value of this parameter can be influenced by both loading conditions and the shape of the prepared samples. By studying the impact of these factors, it is possible to give an adequate assessment of changes in the strength of rocks, as well as to predict their failure behavior. The paper presents the results of experimental studies of hard rocks from the Kola region deposits under uniaxial compression. The values of the rock strength at loading rates from 0.01 to 50 kN/s were established. On the basis of the obtained data it was revealed that the V.A. Fokin criterion can be used to determine the rated strength of rocks. It is shown that the values of uniaxial compressive strength of brittle elastic rock (urtite) and non-brittle elastic-plastic rock (carbonatite) will also increase with the increasing loading rate. It is established that for hard rocks prone to dynamic failure, an increase in the loading rate will lead to an increase in the intensity of their failure. Increasing the loading rate for non-brittle elastic-plastic rocks can cause them to start failing dynamically. The obtained conclusions indicate that the failure behavior of rock samples depends on the time factor of loading.

Keywords: loading rate, uniaxial compressive strength, hard rock, failure of hard rock

For citation: Kozyrev A.A., Kuznecov N.N., Pak A.K. Assessment of the loading rate impact on the uniaxial compressive strength of hard rocks and their failure behavior. Russian Mining Industry. 2024;(1):126–131. (In Russ.) https://doi.org/10.30686/1609-9192-2024-1-126-131

Article info

Received: 23.11.2023

Revised: 10.01.2024

Accepted: 15.01.2024

Information about the authors

Anatolii A. Kozyrev – Dr. Sci. (Eng.), Professor, Chief Scientist of Department of Geomechanics, Mining Institute, Kola Science Centre, Russian Academy of Sciences, Apatity, Russian Federation

Nikolai N. Kuznecov – Cand. Sci. (Eng.), Head of the Laboratory of Instrumental Study of Rock’s State of the Russian Arctic Region, Mining Institute, Kola Science Centre, Russian Academy of Sciences, Apatity, Russian Federation; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Alexandr K. Pak – Researcher of the Laboratory of Instrumental Study of Rock’s State of the Russian Arctic Region, Mining Institute, Kola Science Centre, Russian Academy of Sciences, Apatity, Russian Federation; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

References

1. Wong R.H.С., Chau K.T., Wang P. Microcracking and grain size effect in Yuen Long marbles. International Journal of Rock Mechanics and Mining Sciences and Geomechanics. 1996;33(5):479–485. https://doi.org/10.1016/0148-9062(96)00007-1

2. Stavrogin A.N., Tarasov B.G. Experimental physics and mechanics of rocks. St. Petersburg, Nauka Publ., 2001, 343 p. (In Russ.).

3. Komurlu E. Loading rate conditions and specimen size effect on strength and deformability of rock materials under uniaxial compression. International Journal of Geo-Engineering. 2018;9:17. https://doi.org/10.1186/s40703-018-0085-z

4. Ma H., Song Y., Chen S., Li X., Feng F. Experimental study on effects of loading rate and sample size on the mechanical and failure characteristics of mudstone. Geotechnical and Geological Engineering. 2020;38:2735–2744. https://doi.org/10.1007/s10706-019-01182-8

5. Mansurov V.A., Protosenya A.G. Behavior of rocks at different loading rates. Frunze, Ilim Publ., 1982, 88 p. (In Russ.).

6. Petrov V.A. Statistical kinetics of fracture of heterogeneous solid bodies, Dr. Sci. (Phys.-Math.) diss.: 01.04.12, Leningrad, 1986, 333 p. (In Russ.)

7. Krasko N.I. Investigation of the dependence of rock tensile strength on the time of its loading. Nauchnye trudy Donetskogo natsional'nogo tekhnicheskogo universiteta. Seriya “Gorno-geologicheskaya”. 2002;(54):154–159. (In Russ.) Available at: http:// ea.donntu.ru:8080/bitstream/123456789/15346/1/154-159.pdf (accessed: 13.01.2024).

8. Pak A.K., Kuznetsov N.N. Investigation into the impact of loading rate on the strength properties of medium-grained massive urtite. In: Physical basis of rock fracture prediction: Proceedings of the 9th International Workshop, Irkutsk, September 2-6, 2013, Irkutsk, Russia, 2013 г. Irkutsk IZK SB RAS Publ.; 2013, pp. 62. (In Russ.).

9. Wasantha P.L.P., Ranjith P.G., Zhao J., Shao S.S., Permata G. Strain rate effect on the mechanical behaviour of sandstones with different grain sizes. Rock Mechanics and Rock Engineering. 2014;48:1883–1895. https://doi.org/10.1007/s00603-014-0688-4

10. Efimov V.P. Effect of loading rate on fracture toughness within the kinetic concept of thermal fluctuation mechanism of rock failure. Journal of Mining Science. 2016;52(2):274–278. https://doi.org/10.1134/S1062739116020406

11. Efimov V.P. Experimental study on loading rate effects on the tensile strength and fracture toughness of rocks. Geotechnical and Geological Engineering. 2020;38:6923–6930. https://doi.org/10.1007/s10706-020-01470-8

12. Zhu J., Deng J. A new explanation of loading rate effect on rock compressive strength. IOP Conference Series: Earth and Environmental Science. 2022;1124:012066. https://doi.org/10.1088/1755-1315/1124/1/012066

13. Kuznetsova A.V., Smolin I.Yu. Numerical simulation for mechanical behaviour of rocks around a mine working at different place advance rates. Tomsk State University Journal of Mathematics and Mechanics. 2010;(2):79–87. (In Russ.) Available at: https://journals.tsu.ru/mathematics/en/&journal_page=archive&id=475&article_id=16252 (accessed: 13.01.2024).

14. Kozyrev A.A., Lodus E.V., Kuznetsov N.N. The study of rock properties of the Khibiny massif on shear and uniaxial compression. In: Proceedings of the 6th International Symposium on In-Situ Rock Stress, ISRM Specialized Conference, Sendai, 20–22 August 2013. 2013, pp. 939–952.

15. Jiao M.R., Wong R., Wong T., Chau K.T., Tang C.A. Numerical simulation of the influence of grain size on the progressive development of brittle failure in Yuen Long marbles. Key Engineering Materials. 2004;261-263:1511–1516. https://doi.org/10.4028/www.scientific.net/KEM.261-263.1511

16. Liang C., Wu S., Li X., Xin P. Effects of strain rate on fracture characteristics and mesoscopic failure mechanisms of granite. International Journal of Rock Mechanics and Mining Sciences. 2015;76:146–154. https://doi.org/10.1016/j.ijrmms.2015.03.010

17. Yin X.G.X., Li C., Wang S. Influences of loading rates on mechanical behaviors of rock materials. Chinese Journal of Rock Mechanics and Engineering. 2010;29:2610–2615.

18. Zhou L., Zhu Z., Qiu H., Zhang X., Lang L. Study of the effect of loading rates on crack propagation velocity and rock fracture toughness using cracked tunnel specimens. International Journal of Rock Mechanics and Mining Sciences. 2018;112:25–34. https://doi.org/10.1016/j.ijrmms.2018.10.011

19. Kozyrev A.A.1, Kuznetsov N.N., Fedotova Iu.V., Shokov A.N. The determination of rockburst hazard degree of hard rocks by the test results under uniaxial compression. Izvestiya Vysshikh Uchebnykh Zavedenii. Gornyi Zhurnal. 2019;(6):41–50. (In Russ.) https://doi.org/10.21440/0536-1028-2019-6-41-50

20. Fokin V.A. Determination of uniaxial compressive strength of rocks. Izvestiya Vysshikh Uchebnykh Zavedenii. Gornyi Zhurnal. 2002;(4):20–22. (In Russ.)