Statistical justification for combining host-rock lithotypes by uniaxial compressive strength

The reliability of geomechanical calculations depends on the accuracy with which the strength characteristics of rocks are determined. The aim of this study was to assess the feasibility of combining biotite and amphibole-biotite gneisses into a single design geotechnical element based on uniaxial compressive strength. The initial dataset comprised 146 results of laboratory uniaxial compression tests: 78 for biotite gneisses and 68 for amphibole-biotite gneisses. The data were processed using a standardized algorithm implemented in software developed by the authors. The analysis included assessing the relationship between the parameter and sampling depth, identifying outliers, testing for normality, calculating standard and design values, and comparing sample means and variances. No statistically significant linear relationship was found between rock strength and sampling depth; no outliers were identified; and the hypothesis of a normal distribution was not rejected for either lithotype. The characteristic values for amphibole-biotite and biotite gneisses were 129 MPa, and the design values were 120 MPa. Fisher’s and Student’s tests revealed no statistically significant differences between the samples of the analyzed rock lithotypes. The results supported the validity of combining the considered lithotypes into a single design geotechnical element within the analyzed ferruginous quartzite deposit. For the combined sample, the characteristic and design values were 129 and 123 MPa, respectively.

Tur K. A., Bakhaeva S. P. Statistical justification for combining host-rock lithotypes by uniaxial compressive strength. MIAB. Mining Inf. Anal. Bull. 2026;(11-1):61-73. [In Russ]. DOI: 10.25018/0236_1493_2026_111_0_61.

K.A. Tur¹, Deputy Head of Laboratory, e-mail: kirill.turik@mail.ru, ORCID ID: 0000-0002-7293-3964,
S.P. Bakhaeva¹, Dr. Sci. (Eng.), Professor, Professor, e-mail: bsp.mdg@kuzstu.ru, ORCID ID: 0009-0003-1764-2341,
¹ T.F. Gorbachev Kuzbass State Technical University, 650000, Kemerovo, Russia.

K.A. Tur, e-mail: kirill.turik@mail.ru.

1. Pavlovich A. A., Korshunov V. A., Bazhukov A. A., Melnikov N. Ya. Evaluation of rock mass strength in openpit mining. Journal of Mining Institute. 2019, vol. 239, pp. 502—509. [In Russ]. DOI: 10.31897/PMI.2019.5.502.

2. Bakhaeva S. P., Tur K. A., Ilyushkin V. D. Geomechanical justification of dump stability during joint storage of sandy-clayey overburden and processing waste. Bulletin of the Kuzbass State Technical University. 2020, no. 4, pp. 49—59. [In Russ]. DOI: 10.26730/1999-4125-2020-4-49-59.

3. Kopytov A. I., Masaev Yu. A., Masaev V. Yu. Influence of physical rock properties on the strength characteristics of rock outcrops. Bulletin of the Kuzbass State Technical University. 2023, no. 4 (158), pp. 92—101. [In Russ]. DOI: 10.26730/1999-4125-2023-4-92-101.

4. Carbillet L., Wadsworth F. B., Heap M. J., Baud P. Microstructural controls on the uniaxial compressive strength of porous rocks through the granular to non-granular transition. Geophysical Research Letters. 2023, vol. 50, no. 21, article e2023GL104678. DOI: 10.1029/2023GL104678.

5. Kornilkov S. V., Kharisov T. F., Masalsky N. A., Koptyakov D. A. Study of physical and mechanical properties of rocks in the pit-wall rock mass of PAO Uralasbest. Problems of Subsoil Use. 2025, no. 1 (44), pp. 16—24. [In Russ]. DOI: 10.25635/2313-1586.2025.01.016.

6. Han L., Wang L., Zhang W., Chen Z. Quantification of statistical uncertainties of unconfined compressive strength of rock using Bayesian learning method. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards. 2022, vol. 16, no. 1, pp. 37—52. DOI: 10.1080/17499518.2021.1952612.

7. Chen F., Zhang W. Influence of spatial variability on the uniaxial compressive responses of rock pillar based on three-dimensional random field. ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering. 2021, vol. 7, no. 3, article 04021035. DOI: 10.1061/AJRUA6.0001162.

8. Tur K. A., Kashlinov E. A. «GOST 20522»: Computer Program. Certificate of State Registration of a Computer Program No. 2024692278, registered 27.12.2024. [In Russ].

9. Suprun V. I., Levchenko Ya. V., Kolotovkin A. S., Voroshilin K. S. Size effect on rock strength. MIAB. Mining Inf. Anal. Bull. 2023, no. 10, pp. 5—19. [In Russ]. DOI: 10.25018/0236_1493_2023_10_0_5.

10. Korshunov V. A., Shokov A. N., Dordziev D. Yu., Cherskikh O. I. Studyng the strength properties of weak brittle rocks when testing a point load specimens. MIAB. Mining Inf. Anal. Bull. 2024, no. 11-1, pp. 97—115. [In Russ]. DOI: 10.25018/0236_1493_2024_111_0_97.

11. Petrov D. N., Abashin V. I., Karasev M. A., Selikhov A. A. Non-destructive testing applicability in rock mass strength estimation in underground mine at the Gremyachinsk deposit. MIAB. Mining Inf. Anal. Bull. 2024, no. 12-1, pp. 227—244. [In Russ]. DOI: 10.25018/0236_1493_2024_121_0_227.

12. Morozov I. A. Refinement of the shape factor for salt rocks of the Gremyachinskoye deposit. Gornoe ekho. 2022, no. 3, pp. 19—24. [In Russ]. DOI: 10.7242/echo.2022.3.4.

13. Kozyrev A. A., Kuznetsov 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 Journal. 2024, no. 1, pp. 126—131. [In Russ]. DOI: 10.30686/1609-9192-2024-1-126-131.

14. Rysin A. I., Nurtdinov A. S., Rumyantseva N. A., Lebedeva A. M. Effect of chloride-rock specimen shape on the accuracy of uniaxial compressive-strength determination. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering. 2026, vol. 337, no. 3, pp. 192—201. [In Russ]. DOI: 10.18799/24131830/2026/3/5097.

15. Xie W.-Q., Liu X.-L., Zhang X.-P., Liu Q.-S., Wang E.-Z. A review of test methods for uni-axial compressive strength of rocks: Theory, apparatus and data processing. Journal of Rock Mechanics and Geotechnical Engineering. 2025, vol. 17, no. 3, pp. 1889—1905. DOI: 10.1016/j.jrmge.2024.05.003.

16. Burbaum U. Stress-rate dependency of uniaxial compressive strength of hard rock with regard to test procedure standards. Bulletin of Engineering Geology and the Environment. 2023, vol. 82, article 4. DOI: 10.1007/s10064-022-03024-z.

17. Šancer J., Široký T., Krenžel V. Determination of the uniaxial compressive strength of rocks from the strength index. GeoScience Engineering. 2022, vol. 68, no. 2, pp. 158—166. DOI: 10.35180/gse-2022-0078.

18. Aladejare A. E., Idowu K. A., Ozoji T. Reliability of Monte Carlo simulation approach for estimating uniaxial compressive strength of intact rock. Earth Science Informatics. 2024, vol. 17, no. 3, pp. 2043—2053. DOI: 10.1007/s12145-024-01262-1.

19. Aladejare A. E., Alofe E. D., Onifade M., Lawal A. I., Ozoji T. M., Zhang Z.-X. Empirical estimation of uniaxial compressive strength of rock: Database of simple, multiple, and artificial intelligence-based regressions. Geotechnical and Geological Engineering. 2021, vol. 39, no. 6, pp. 4427—4455. DOI: 10.1007/s10706-021-01772-5.

20. Xue X. A novel model for prediction of uniaxial compressive strength of rocks. Comptes Rendus Mécanique. 2022, vol. 350, pp. 159—170. DOI: 10.5802/crmeca.109.

21. Hassan M. Y., Arman H. Several machine learning techniques comparison for the prediction of the uniaxial compressive strength of carbonate rocks. Scientific Reports. 2022, vol. 12, article 20969. DOI: 10.1038/s41598-022-25633-0.