Investigation of influence of clay inclusions and insoluble residue content on rib pillar stability by numerical modeling of stratified media in terms of potash deposits

Numerical modeling was performed to analyze the influence of clay interbeds and insoluble residue on load-bearing capacity of rib pillars in salt rock mass. The modeling results show that the change in the strength at the increasing content of the insoluble residue has a distinct nonlinear behavior: at the content to 5%, the highest decrease is observed; the higher content leads to the drop in the load-bearing capacity to 30–40% of the salt rock level. It is found that the determining factor is appearance of the first clay interbed, while an increase in their number over 12–16 interbeds has no influence on the final load-bearing capacity. The strength ratio of salt rocks and clay interbeds defines the shape of the weakening curve, and the highest influence is exerted by the decrease in cohesion of clay material. The geometrical parameters also play an important role: the increase of the height-to-width ratio of a pillar increases the influence of clay interbeds, and the presence of a thick weak interbed in the roof decreases the load-bearing capacity additionally by 15–25%. The obtained dependences demonstrate that the use of only percentage of the insoluble residue is insufficient for the reliable assessment of pillars. The practical relevance of the research consists in the revision of the concept on the influence exerted by clay interbeds on the load-bearing capacity of rib pillars, and in the substantiation of transition to the multi-factor stability assessment of pillars in interstratified salt strata.

Karasev M. A., Otkupshchikova I. A., Rysin A. I., Lebedeva A. M., Nurtdinov A. S. Investigation of influence of clay inclusions and insoluble residue content on rib pillar stability by numerical modeling of stratified media in terms of potash deposits. MIAB. Mining Inf. Anal. Bull. 2026;(11):33-51. [In Russ]. DOI: 10.25018/0236_1493_2026_11_0_33.

M.A. Karasev¹, Dr. Sci. (Eng.), Assistant Professor, Professor, e-mail: karasev_MA@pers.spmi.ru, ORCID ID: 0000-0001-8939-0807,
I.A. Otkupshchikova¹, Graduate Student, e-mail: otkupschikova2015@gmail.com, ORCID ID: 0009-0002-6232-8733,
A.I. Rysin², Head of Laboratory, e-mail: aleksandr.rysin@pte.eurochem.ru, ORCID ID: 0009-0005-3489-2195,
A.M. Lebedeva, Graduate Student, Lomonosov Moscow State University, 119991, Moscow, Russia, e-mail: amlebedeva07@gmail.com, ORCID ID: 0009-0005-8046-364X,
A.S. Nurtdinov², Chief Specialist, e-mail: anton.nurtdinov@pte.eurochem.ru,
¹ Empress Catherine II Saint-Petersburg Mining University, 199106, Saint-Petersburg, Russia,
² LLC «ProTech Engineering», 199178, Saint-Petersburg, Russia.

I.A. Otkupshchikova, e-mail: otkupschikova2015@gmail.com.

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