Institute of Continuous Media Mechanics—Division of the Perm Federal Researcher Center, Ural Branch, Russian Academy of Science, Perm, Russia

Panteleev I. A., Head of Laboratory, Doctor of Physical and Mathematical Sciences

Mining Institute—Division of the Perm Federal Researcher Center, Ural Branch, Russian Academy of Science, Perm, Russia

Lomakin I. S., Senior Researcher, Candidate of Engineering Sciences

Perm Federal Researcher Center, Ural Branch, Russian Academy of Science, Perm, Russia

Baryakh A. A., Professor, Doctor of Engineering Sciences, Academician of the Russian Academy of Sciences, bar@Mi-Perm.ru

The study assesses the effect of including the decrease in elastic properties of salt rocks in calculation of the bearing capacity of different-size rib pillars under varying effective pressure. Based on the review of domestic and foreign reference sources, we selected the correlation between the change in the uniaxial compression strength and the decrease in Young’s modulus. A modification of the approach to estimation of loading of rib pillars is proposed. It is based on the mathematical modeling of normalized stress intensity at the central point of a pillar. In this article, this calculation model is implemented as a case-study of productive sylvinite stratum Kr II at the Verkhnekamskoe (Upper Kama) salt deposit. The approximation relationships for the decrease in elastic properties with an increase in maximum effective stress are based on the results of laboratory experiments on step-by-step uniaxial compression of sylvinite specimens. Based on the results of computational experiments, we find that the dependence of elastic properties of sylvinite on maximum principal stress has the most significant impact on the load-bearing capacity of pillars with width-to height ratios of no more than 1 at the effective pressure of total undermining. For instance, the maximum change in the degree of loading of the rib pillar is 26%, from 0.5 to 0.63, and this occurs for a pillar with a shape factor of 0.75.

The work was carried out as part of a major scientific project supported by the Ministry of Science and Higher Education of the Russian Federation, Agreement No. 075-15-2024-535 dated 23 April 2024.

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