Mekhanobr Tekhnika Research and Engineering Corporation, Saint Petersburg, Russia:

L. A. Vaisberg, Academician of the Russian Academy of Sciences, Doctor of Engineering Sciences

Petrozavodsk State University, Petrozavodsk, Russia:

E. E. Kameneva, Head of Laboratory, Associate Professor, Candidate of Engineering Sciences, elena.kameneva@mail.ru

The search for the methods and modes of destruction of mineral aggregates at the minimized energy consumption is the main task of rock disintegration. According to modern ideas about the mechanism of disintegration, destruction of rocks is a process that evolves over time. From the moment of load application, the elastic and plastic deformations develop in rocks, and the elastic/plastic strain ratios depend both on the textural and structural features of rocks, and on the loading parameters. The effects of the loading rate on the pore space structure of rocks were studied. Samples of granite and gabbro-diabase were investigated. This samples had different texture, structure and porosity. The studies were performed using X-ray computer microtomography (X-ray micro-CT). This method allows obtaining quantitative values of the porosity structure – size, quantity, concentration, specific surface area of pores. The loading rate range was 0.5–5.0 mPa/s. The value of the loading force was ≈50% of the ultimate compressive strength. The load type was uniaxial compression. It is found that the porosity, as well as the number and concentration of pores under the action of axial load are reduced, the samples are compacted, small pores are closed and large non-spherical pores appear. The decrease in the total porosity and pore concentration in the samples grows with increasing loading rate. The degree of porosity reduction also depends on the structure and strength of the rocks. In granites (weaker rocks), the indicators vary greatly. In gabbro-diabase (more durable low-porous rock), the porosity parameters change less significantly.
The study was supported by the Russian Science Foundation, Project No. 17-79-30056.

1. Rzhevsky V. V., Novik G. Ya. Basis of physics of rocks : Textbook. 4^th edition, revised and enlarged. Moscow : Nedra, 1984. 359 p.
2. Revnivtsev V. I., Gaponov G. V., Zarogatskiy L. P. Selective destruction of minerals. Moscow : Nedra, 1988. 430 p.
3. Stavrogin A. N., Protosenya A. G. Rock deformation and fracture mechanics. Moscow : Nedra, 1992. 224 p.
4. Mansurov V. A., Protosenya A. G. Behavior of rocks under different rates of loading. Frunze : Ilim, 1982. 88 p.
5. Khopunov E. А. Role of loading factors in selective disintegration of ores. Obogashchenie Rud. 2011. No. 2. pp. 27–34.
6. Yan Chen, Jianping Zuo, Baohua Guo, Wenbing Guo. Effect of cyclic loading on mechanical and ultrasonic properties of granite from Maluansh an Tunnel. Bulletin of Engineering Geology and Environment. 2020. Vol. 79, Iss. 1. pp. 299–311.
7. Volkov M. A., Pimonov A. G. Modeling kinetics of fracturing in rocks at different stages of deformation. Vestnik Kuzbasskogo gosudarstvennogo tekhnicheskogo universiteta. 2007. No. 6(64). pp. 99–104.
8. Pavlova N. N., Shreyner L. A. Rock fracture in dynamic loading. Moscow : Nedra, 1964. 160 p.
9. Yagodkin G. I., Mokhnachev M. P., Kuntysh M F. Strength and deformability of rocks in loading. Moscow : Nauka, 1971. 148 p.
10. Özdemir E., Eren Sarici D. Combined Effect of Loading Rate and Water Content on Mechanical Behavior of Natural Stones. Journal of Mining Science. 2018. Vol. 54, Iss. 6. pp. 931–937.
11. 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. Vol. 52, Iss. 2. pp. 274–278.
12. Skipochka S. I., Palamarchuk T. A., Yalanskiy A. A., Bobro N. T., Prokhorets L. V. Effect of loading rate on strength characteristics of rocks. Geotechnical Mechanics : Interdepartmental Collection of Scientific Papers. Dnepropetrovsk : IGTM NANU, 2016. No. 126. pp. 116–127.
13. Peng S. S. A note on the fracture propagation and time-dependent behavior of rocks in uniaxial tension. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. 1975. Vol. 12, Iss. 4. pp. 125–127.
14. Yakushina O. A., Ozhogina E. G., Khozyainov M. S., Astakhova Yu. M., Iospa A. V. X-ray tomography for the morphrostructural analysis of mineral substance. Physical-Chemical and Petrophysical Researches in the Earth’s Sciences : The 19^th International Conference Proceedings. Moscow : IGEM RAN, 2018. pp. 372–375.
15. Pini R., Madonna C. Moving across scales: a quantitative assessment of X-ray CT to measure the porosity of rocks. Journal of Porous Materials. 2016. Vol. 23, Iss. 2. pp. 325–338.
16. Callow B., Falkon-Suarez I., Marin-Moreno H., Bull J. M., Ahmed S. Optimal X-ray micro-CT image based methods for porosity and permeability quantification in heterogeneous sandstones. Geophysical Journal International. 2020. Vol. 223, Iss. 2. pp. 1210–1229.
17. Talovina I. V., Aleksandrova T. N., Popov O., Lieberwirth H. Comparative analysis of rocks structuraltextural characteristics studies by computer X-ray microtomography and quantitative microstructural analysis methods. Obogashchenie Rud. 2017. No. 3. pp. 56–62. DOI: 10.17580/or.2017.03.09
18. Vaisberg L. A., Kameneva E. E. X-ray computed microtomography as the basis for mineral processing improvement : review. Eurasian Mining. 2020. No. 1. pp. 46–52. DOI: 10.17580/em.2020.01.09
19. Vaisberg L. A., Kameneva E. E. Study on changes in the porosity structure of rocks at different loading stages. Obogashchenie Rud. 2019. No. 3. pp. 37–42. DOI: 10.17580/or.2019.03.06
20. Menzhulin M. G., Makhmudov Kh. F., Kuksenko V. S., Sultonov U. Formation and development of focus destruction of natural strain heterogeneous materials. Vestnik Tambovskogo universiteta. Ser. Estestvennye i tekhnicheskie nauki. 2013. Vol. 18, No. 4-2. pp. 1667–1668.
21. Kuksenko V. S., Makhmudov K. F., Mansurov V. A., Sultonov U., Rustamova M. Z. Changes in Structure of Natural Heterogenous Materials Under Deformation. Journal of Mining Science. 2009. Vol. 45, Iss. 4. pp. 355–358.