Modeling displacements and stress relief in coal-bearing rock mass

The article analyzes the key stress redistribution patterns in coal-bearing rock mass and in the coal seam roof and floor at the stage of pre-mine gas drainage. The known experimentally revealed property of coal samples to change their linear sizes in methane absorption– desorption is used to construct theoretical models of the influence exerted by gas emission from coal seam on the stress–strain behavior of enclosing rock mass. Naturally, coal mining greatly changes the rock mass behavior and induces zones of stress relief and stress increase in rocks. On the other hand, rock mass undergoes impact of gas drainage activities as early as before mining, and stress relief zones also appear in this case although they are weaker. As known, these zones induce or stimulate permeability in rock mass and, accordingly, promote mass transfer of methane to drainage boreholes among other things. The analytical problem is solved by means of adaptation of the known relations from theory of functions of complex variable and the solution of the Kelvin problem on an elastic half-space subject to a load. The article shows that beyond the stress relief zone, there is a stress increase zone in rock mass, which is the strongest nearby the gas drainage zone boundary, and the stress relief front is simultaneously the stress increase front.

Zakharov V. N., Trofimov V. A., Shlyapin A. V. Modeling displacements and stress relief in coal-bearing rock mass. MIAB. Mining Inf. Anal. Bull. 2022;(12):109-127. [In Russ]. DOI: 10.25018/0236_1493_2022_12_0_109.

The study was supported by the Ministry of Science and Higher Education of the Russian Federation, Agreement No. 075-15-2021-943 and European Commission Research Fund for Coal and Steel (RFCS) funded project «Advanced methane drainage strategy employing underground directional drilling technology for major risk prevention and green-house gases emission mitigation» GA: 847338-DD-MET-RFCS-2018/RFCS-2018.

V.N. Zakharov¹, Аcademician of Russian Academy of Sciences, Director ICEMR RAS, e-mail: ipkon-dir@ipkonran.ru, ORCID ID: 0000-0002-9309-2391,
V.A. Trofimov¹, Dr. Sci. (Eng.), Head of Laboratory, e-mail: asas_2001@mail.ru, ORCID ID: 0000-0001-9010-189X,
A.V. Shlyapin¹, Cand. Sci. (Eng.), Deputy Director for Science, e-mail: Shlyapin@mail.ru, ORCID ID: 0000-0002-9442-0983,
¹ Institute of Problems of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences, 111020, Moscow, Russia.

A.V. Shlyapin, e-mail: Shlyapin@mail.ru.

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