Size effect on rock strength

The article reviews the studies into the uniaxial compressive strength of different-size rock samples and analyzes some major theories of impact exerted by size effect on the strength limit. Numerous researches disclose different laws of this phenomenon. As rock samples grow in size, their strength can decrease, increase, remain the same or alternate. In order to add the available knowledge, we carried out experiments on estimation of the size effect in sedimentary, metamorphic and magmatic rock samples made as cubes 20×20×20 mm to 60×60×60 mm in size. The influence of alternate freezing and thawing on the strength limit was studied for 21 types of rocks with regard to their average dry density. We also tested strength of samples cut out from different height-wise zones in the same laminated layer of Myachkovo limestone. The influence of lamination and strength nonuniformity is tested depending on the direction of the compressive load applied. Using the obtained results with a view to improving accuracy of testing, the recommendations on the sizes and number of samples are given in accordance with state standard GOST 30629-2011. It is concluded that the obtained results on strength of rock samples are applicable to estimating strength properties in rock mass.

Suprun V. I., Levchenko Ya. V., Kolotovkin A. S., Voroshilin K. S. Size effect on rock strength. MIAB. Mining Inf. Anal. Bull. 2023;(10):5-19. [In Russ]. DOI: 10.25018/ 0236_1493_2023_10_0_5.

V.I. Suprun¹, Dr. Sci. (Eng.), Director PEC of NUST «MISIS», e-mail: labstone@mail.ru, ORCID ID: 0000-0003-4585-8003,
Ya.V. Levchenko¹, Cand. Sci. (Eng.), Assistant Professor, e-mail: levchenko.mggu@mail.ru, ORCID ID: 0000-0002-2080-6330,
A.S. Kolotovkin¹, Graduate Student, e-mail: kolotovkin1904@mail.ru,
K.S. Voroshilin¹, Senior Lecturer, e-mail: k.voroshilin@yandex.ru,
¹ Mining Institute, National University of Science and Technology «MISiS», 119049, Moscow, Russia.

Ya.V. Levchenko, e-mail: levchenko.mggu@mail.ru.

1. Zhabin A. B., Polyakov A. V., Averin E. A., Linnik Yu. N., Linnik V. Yu. Integrated effect of size on ultimate compressive strength of rock samples. MIAB. Mining Inf. Anal. Bull. 2022, no. 8, pp. 5—13. [In Russ]. DOI: 10.25018/0236_1493_2022_8_0_5.

2. Sultanalieva R. M., Konushbaeva A. T., Turdubaeva Сh. B. Determination of strength indicators of rocks under uniaxial compression and tension. International journal of applied and fundamental research. 2021, no. 5, pp. 61—66. [In Russ].

3. Koifman M. I. Main scale effect in rocks and coals. Problemy mekhanizatsii gornykh rabot [Problems of mechanization of mining works], Moscow, Izd-vo AN SSSR, 1963, pp. 39—56.

4. Koyfman M. I. On the effect of dimensions on the strength of rocks. Issledovanie fizikomekhanicheskikh svoystv gornykh porod primenitel'no k zadacham upravleniya gornym davleniem [Research of physical and mechanical properties of rocks as applied to the problems of rock pressure control], Moscow, Izd-vo AN SSSR, 1962, pp. 6—14.

5. Ermolovich E. A., Ovchinnikov A. V., Anikeev A. A., Haustov V. V. Influence of sample dimensions on chalk strength. News of the Tula state university. Sciences of Earth. 2020, no. 2, pp. 263—271. [In Russ].

6. Komurlu E. Loading rate conditions and specimen size effect on strength and deformability of rock materials under uniaxial compression. Geo-Engineering. 2018, vol. 9, no. 17, pp. 1—11. DOI: 10.1186/s40703-018-0085-z.

7. Honghua Songa, Yaodong Jiangb, Derek Elsworthd, Yixin Zhaoa, Jiehao Wangd, Bin Liua Scale effects and strength anisotropy in coal. International Journal of Coal Geology. 2018, vol. 195, pp. 37—46. DOI: 10.1016/j.coal.2018.05.006.

8. Baron L. I., Kurbatov V. M. On the influence of the scale factor in crushing tests of rocks. Nauchnye issledovaniya po razrabotke ugol'nykh i rudnykh mestorozhdeniy [Scientific research on development of coal and ore deposits], Moscow, Gosgortekhizdat, 1959, pp. 128—136.

9. Shirko G. I. On calculations of inter-chamber pillars at chamber development system. Issledovaniya solyanykh mestorozhdeniy i mineral'nykh vod. Trudy Vsesoyuznogo nauchno-issledovatel'skogo instituta metallurgii, vyp. XXVIII [Investigations of salt deposits and mineral waters. Proceedings All-Union Scientific Research Institute of Metallurgy, issue XXVIII], Moscow, Goskhimizdat, 1953, 152 p.

10. Melikidze I. G. About influence of form and sizes of samples on their mechanical properties. Gornyi Zhurnal. 1955, no. 9, pp. 35—39. [In Russ].

11. Il'nitskaya E. I., Teder R. I., Vatolin E. S., Kuntysh M. F. Svoystva gornykh porod i metody ikh opredeleniya [Properties of rocks and methods of their determination], Moscow, Nedra, 1969, 392 p.

12. Alejano L. R., Walton G., Gaines S. Residual strength of granitic rocks. Tunnelling and Underground Space Technology. 2021, vol. 118, article 104189. DOI: 10.1016/j.tust.2021.104189.

13. Verbilo P. E. Otsenka prochnosti i deformirovaniya mezhdukamernykh tselikov v blochnom gornom massive [Assessment of strength and deformation of inter-chamber pillars in a block mountain massif], Candidate’s thesis, Saint-Petersburg, 2018, 150 p.

14. Verbilo P. E., Vilne M. A. Study of the jointed rock mass uniaxial compression strength anisotropy and scale effect. MIAB. Mining Inf. Anal. Bull. 2022, no. 6-2, pp. 47—59. [In Russ]. DOI: 10.25018/0236_1493_2022_62_0_47.

15. Kuznetsov N. N., Pak A. K. Influence of the hard rock specimens’ size ratio on the results of their strength determination under uniaxial compression. Vestnik MGTU. Trudy Murmanskogo gosudarstvennogo tekhnicheskogo universiteta. 2014, vol. 17, no. 2, pp. 246—253. [In Russ].

16. Kun Du, Xuefeng Li, Rui Su, Ming Tao, Shizhan Lv, Jia Luo, Jian Zhou Shape ratio effects on the mechanical characteristics of rectangular prism rocks and isolated pillars under uniaxial compression. International Journal of Mining Science and Technology. 2022, vol. 32, pp. 347—362. DOI: 10.1016/j.ijmst.2022.01.004.

17. Durmeková T., Bednarik M., Dikejová P., Adamcova R. Influence of specimen size and shape on the uniaxial compressive strength values of selected Western Carpathians rocks. Environmental Earth Sciences. 2022, vol. 81, no. 9. DOI: 10.1007/s12665-022-10373-1.

18. Usol’tseva O. M., Tsoi P. A., Semenov V. N. Sample size influence on stress-strain properties of rocks. Mining sciences: fundamental and applied issues. 2020, vol. 7, no. 2, pp. 53—59. [In Russ]. DOI: 10.15372/FPVGN2020070209.

19. Sefer Beran Çelik The effect of cubic specimen size on uniaxial compressive strength of carbonate rocks from Western Turkey. Arabian Journal of Geosciences. 2017, vol. 10, no. 19. DOI: 10.1007/s12517-017-3218-3.

20. Baryakh A. A, Asanov V. A., Pankov I. L., Toksarov V. N., Kirisyuk M. A. Researches on scale effect in salt rocks. MIAB. Mining Inf. Anal. Bull. 2010, no. 10, pp. 141—144. [In Russ].

21. Tsai B. N. Scale factor at the rock strength assessment. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal. 2009, no. 3, pp. 59—64. [In Russ].

22. Shashenko A. N., Sdvizhkova E. A., Kuzhel' S. V. Masshtabnyy effekt v gornykh porodakh: Monografiya [Scale effect in rocks. Monograph], Donetsk, Izd-vo «Nord-Press», 2004, 126 p.

23. Zingano A. C. Estimating coal strength based on historical laboratory tests and geomechanics classification. Aspects in Mining & Mineral Science. 2020, vol. 5, no. 4, article 000618. DOI: 10.31031/AMMS.2020.05.000618.

24. Borshch-Komponiets V. I. Prakticheskaya mekhanika gornykh porod [Practical mechanics of rocks], Moscow, Izd-vo «Gornaya kniga», 2013, 322 p.

25. Suprun V. I., Artem'ev V. B., Opanasenko P. I. Perspektivnaya tekhnika i tekhnologii dlya proizvodstva otkrytykh gornykh rabot [Perspective Technique and technology for the production of surface mining], Moscow, Kimmeriyskiy tsentr, 2017, 208 p.

26. Fotografiya borta kar'era po dobyche mramora [Photo of the side of the marble quarry], available at: http://www.detaymarble.com/?p=361 (accessed 21.01.2023). [In Russ].

27. Fotografiya borta kar'era po dobyche travertina [Photo of the side of the quarry for travertine extraction], available at: http://tekmarble.com/sayfa/galeri/ (accessed 21.01.2023). [In Russ].

28. Reed J., Stacy P. Rukovodstvo po proektirovaniyu bortov kar'era [A guide to quarry slope design], Ekaterinburg, Pravoved: Polimetall, 2015, 527 p.

29. Ruppeneyt K. V. Deformiruemost' massivov treshchinovatykh gornykh porod [Deformability of massifs of fractured rocks], Moscow, Nedra, 1975, 223 p.