Pro-Tech–Engineering LLC, Saint-Petersburg, Russia

A. I. Rysin, Head of Laboratory

A. S. Nurtdinov, Chief Specialist

Lomonosov Moscow State University, Moscow, Russia
A. M. Lebedeva, Post-Graduate Student, amlebedeva07@gmail.com

Empress Catherine II Saint-Petersburg Mining University, Saint-Petersburg, Russia
I. A. Otkupshchikova, Post-Graduate Student

The key parameters of the mining system adopted at the Upper Kama Potassium–Magnesium Salt deposit (UKPMS) are conditioned by some important geomechanical characteristics: content of insoluble residue; strength and stability of rocks; depth of occurrence; lithology; thickness and hypsometry of productive strata, etc. For this reason, the nonuniformity is observed in the physical and mechanical properties of rocks even within the limits of provisionally uniform beds. The difference in the stress–strain behavior of salt and non-salt materials governs various stress patterns in rock masses. The influence of the insoluble impurities on the load-bearing capacity of rib pillars in salt rock mining is investigated. The aim of the investigation was to improve the loading calculation procedure for rib pillars under conditions of the increased content of clays at UKPMS. The lab-scale tests provided new data on variation in the strength of salt rocks depending on the content of the insoluble residue (ISR) in a range from 0 to 100 %. Based on the obtained data, the standard clayness index curve was adjusted to the geological conditions of the Usolie Potassium Deposit. On the whole, the existing procedures for assessing influence of the ISR content on the load-bearing capacity of pillars require revision, and the research findings in this article are not a final output and need the experimental and theoretical data base on the rock mass behavior to be expanded and analyzed. The further research will be aimed at updating the reported studies on strength dependence on patterns of clayey interbeds in rock pillars, at obtaining new data and at determining parameters for the numerical model of deformation of salt rocks and clayey interbeds.

1. Baryakh A. A., Evseev A. V., Lomakin I. S., Tsayukov A. A. Operational control of rib pillar stability. Eurasian Mining. 2020. No. 2. pp. 7–10.
2. Tsarev R. I., Prigara А. М., Zhukov А. А., Mitskevich А. А. Monitoring of geological environment during mining using land and in-mine seismic surveys. Eurasian Mining. 2024. No. 2. pp. 38–42.
3. Baryakh A.A., Andreiko S.S., Fedoseev A.K. Gas-dynamic roof fall during the potash deposits development. Journal of Mining Institute. 2020. Vol. 246. pp. 601–609.
4. Wang G., Guo K., Christianson M., Konietzky H. Deformation characteristics of rock salt with mudstone interbeds surrounding gas and oil storage cavern. International Journal of Rock Mechanics and Mining Sciences. 2011. Vol. 48, Iss. 6. pp. 871–877.
5. Yan Z., Wang Z., Wu F., Lyu C. Stability analysis of Pingdingshan pear-shaped multimudstone interbedded salt cavern gas storage. Journal of Energy Storage. 2022. Vol. 56. ID 105963.
6. Yin H., Yang C., Ma H., Shi X., Zhang N. et al. Stability evaluation of underground gas storage salt caverns with micro-leakage interlayer in bedded rock salt of Jintan, China. Acta Geotechnica. 2020. Vol. 15, Iss. 3. pp. 549–563.
7. Zhao Y., Wang X., Tang W., Li Y., Lin X. et al. Creep behavior of layered salt rock under triaxial loading and unloading cycles. Applied Rheology. 2023. Vol. 33. DOI: 10.1515/arh-2023-0103
8. Xu Y., Liao X., Li J., Chen L., Li L. The effects of water content and dry–wet cycles of weak‐interlayer soil on stability of clastic rock slope. Geotechnical and Geological Engineering. 2021. Vol. 39. pp. 3753–3760.
9. Zhang Z., Wang T. Failure modes of weak interlayers with different dip angles in red mudstone strata, Northwest China. Bulletin of Engineering Geology and the Environment. 2023. Vol. 82, Iss. 5. DOI: 10.1007/s10064-023-03165-9
10. Li Y., Liu W., Yang C., Daemen J. J. K. Experimental investigation of mechanical behavior of bedded rock salt containing inclined interlayer. International Journal of Rock Mechanics and Mining Sciences. 2014. Vol. 69. pp. 39–49.
11. Liang W., Zhao Y., Xu S., Dusseault M. B. Soft interlayer effect on the mechanical behavior of bedded salt rock. Mechanical Behavior of Salt VII : Proceedings of the 7^th Conference on the Mechanical Behavior of Salt. Boca Raton : CRC Press, 2012. pp. 23–30.
12. Ilyinov M. D., Petrov D. N., Karmanskiy D. A., Selikhov A. A. Physical simulation aspects of structural changes in rock samples under thermobaric conditions at great depths. Mining Science and Technology. 2023. Vol. 8, No. 4. pp. 290–302.
13. Ilinov M. D., Korshunov V. A., Pospekhov G. B., Shokov A. N. Integrated experimental research of mechanical properties of rocks: Problems and solutions. Gornyi Zhurnal. 2023. No. 5. pp. 11–18.
14. Gospodarikov A. P., Kirkin A. P., Trofimov A. V., Kovalevsky V. N. Determination of physical and mechanical properties of rocks using anti-burst destress measures. Gornyi Zhurnal. 2023. No. 1. pp. 26–34.