Deformation of underground excavations under conditions of the Gremyachinsk potassium salt deposit

The analysis of rock mass deformation around permanent excavations in sylvinite seam at a depth of 1100 m is presented. Surrounding rock mass features occurrence of hard anhydrite–dolomite rocks in the roof and soft carnallite in the floor of underground excavations. The test openings were driven with height of 3.7 m and width of 6.0 m using a cutter– loader. The deformation control used 6 measurement points in the excavations with support by rockbolting in the patterns of 1.0×1.0, 1.5×1.5 and 2.0×2.0 m. Two measurement points were arranged in an unsupported excavation. It is found that the key factors influencing deformation of the perimeter of underground excavations are the rockbolting design and the geological structure of enclosing rock mass. For instance, the reinforcement of roof support decreases values and velocities of deformation both in the roof and sidewalls of excavations. The highest values of velocities of displacements are recorded in the floor. The increased displacements in the floor rocks should be expected when the distance between the excavation perimeter and the nearest interface of seams (layers) in the floor of a tunnel decreases. The presented results can be of use to experts in the fields of geomechanics as well as in design and construction of underground excavations.

Toksarov V. N., Morozov I. A., Beltyukov N. L., Udartsev A. A. Deformation of underground excavations under conditions of the Gremyachinsk potassium salt deposit. MIAB. Mining Inf. Anal. Bull. 2020;(7):113-124. [In Russ]. DOI: 10.25018/0236-1493-2020-7-0-113-124.

The study was carried out under State Contract No. NIOKTR AAAAA18-118040690032-2 and was supported by the Russian Foundation for Basic Research and by the Perm Krai, Project No. 19-45-590004.

V.N. Toksarov¹, Cand. Sci. (Eng.), Senior Researcher,
I.A. Morozov¹, Engineer, e-mail: imorozov.work@yandex.ru,
N.L. Beltyukov¹, Cand. Sci. (Eng.), Researcher,
A.A. Udarcev¹, Junior Researcher,
¹ Mining Institute of Ural Branch, Russian Academy of Sciences, 614007, Perm, Russia.

I.A. Morozov, e-mail: imorozov.work@yandex.ru.

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