Effects of temperature field nonuniformity on strength of frozen wall in mine shafts

This article presents the quantitative analysis of spatial nonuniformity of frozen wall strength versus resultant thickness based on the Mohr–Coulomb failure criterion. The strength nonuniformity is caused by the nonuniformity of temperature field of the frozen wall. The calculation uses the limit values of long-term cohesion and internal friction angle obtained in experimental core tests of seven rock types. The core sampling was carried out at the industrial infrastructure of a potassium mine under construction in the Republic of Belarus. The onedimensional model computation shows that the temperature field nonuniformity of the frozen wall leads to the nonuniformity of its strength characteristics and results in the excessive minimum allowable thickness (required thickness) of the frozen wall as against the uniform field of temperatures of the same average value. The increment of the frozen wall thickness under nonuniform temperature in frozen rocks (at the maximum temperature variation of 10–12 °С) for seven test types of rocks lies in the range from 24 to 50%. The functional dependence of the required frozen wall thickness on the maximum temperature variation in frozen rocks is determined: this is a power law with an exponent of 0.5 for all test types of rocks.

Semin M. A., Brovka G. P., Pugin A. V., Bublik S. A., Zhelnin M. S. Effects of temperature field nonuniformity on strength of frozen wall in mine shafts. MIAB. Mining Inf. Anal. Bull. 2021;(9):79-93. [In Russ]. DOI: 10.25018/0236_1493_2021_9_0_79.

The study was supported by the Russian Science Foundation, Project No. 17-11-01204.

M.A. Semin¹, Cand. Sci. (Eng.), Researcher, e-mail: seminma@inbox.ru,
G.P. Brovka, Dr. Sci. (Eng.), Assistant Professor, Head of the Laboratory, Institute of Nature Management of National Academy of Sciences, 220114, Minsk, Republic of Belarus,
A.V. Pugin¹, Cand. Sci. (Phys. Mathem.), Researcher, e-mail: lyosha.p@gmail.com,
S.A. Bublik¹, Graduate Student, Engineer, e-mail: serega-bublik@mail.ru,
M.S. Zhelnin, Graduate Student, Junior Researcher, Institute of Continuous Media Mechanics, Ural Branch of Russian Academy of Sciences, 614013, Perm, Russia, e-mail: zhelninmax@gmail.com,
¹ Mining Institute, Ural Branch of Russian Academy of Sciences, 614007, Perm, Russia.

M.A. Semin, e-mail: seminma@inbox.ru.

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