About One Approach to the Calculation of Coal Outburst from Gas-bearing Seam Hosting Geological Disturbances


Annotation:

The model of the geomechanical state of the coal seam hosting the «weak» layer and the geological disturbance, which is a reservoir with the compressed methane, is built on the fundamental methods of solid mechanics. Condition for coal burst into the working is the imbalance of part of the layer under the influence of methane pressure in the reservoir located at a distance critical from the edge of the bed and the friction forces at the contact of the layer and the coal bed. The stress state in the layer is determined by numerical calculation of the boundary problems of the limit state theory for the number of the specific sections. The friction forces are calculated by integrating tangential stresses found during solution of boundary value problems along the layer contact with the seam.

Within the framework of the developed model, the computational experiment was conducted for the number of characteristics of strength and power of the layer and the curve parameter describing the change in the pressure of the free methane in the coal seam. The graphs that establish the relationship between the characteristics of the strength of the layer and its critical length corresponding to the beginning of the outburst are smoothly decreasing gentle curves. It is shown that with an increase in the thickness of the layer, the values of the critical length corresponding to the outburst also increase, while the strength characteristics of the layer also increase.

Quantitative estimates are given between the critical length of the «weak» layer and the value of the parameter characterizing the intensity of methane pressure growth. It is established that at the values of this parameter corresponding to the achievement of hydrostatic pressure by the methane pressure in the close vicinity to the seam edge, the coal outburst can occur at rather high characteristics of the layer strength.

References:
  1. Petukhov I.M., Linkov A.M. Mechanics of rock bumps and outburst. Moscow: Nedra, 1983. 280 p. (In Russ.).
  2. Chernov O.I., Puzyrev V.N. Forecast of sudden coal and gas outburst. Moscow: Nedra, 1979. 296 p. (In Russ.).
  3. Malyshev Yu.N., Trubetskoy K.N., Ayruni A.T. Fundamental and applied methods for solving the problem of coal seams. Moscow: IAGN, 2000. 519 p. (In Russ.).
  4. Shadrin A.V. Static and Dynamic Outburst Hazard of Coal Seams. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2018. № 4. pp. 42–48. (In Russ.). DOI: 10.24000/0409-2961-2018-4-42-48
  5. Shadrin A.V. Effect of simplifying the methodology for the current forecast of the outburst hazard of coal seams on the reliability of the forecast. Vestnik Nauchnogo tsentra VostNII po bezopasnosti rabot v ugolnoy promyshlennosti = Bulletin of the VostNII Scientific center for safety of work in the coal industry. 2017. № 2. pp. 31–33. (In Russ.).
  6. Kozyreva E.N. Possibilities for improving the efficiency of gas release control at the working area. Vestnik Nauchnogo tsentra VostNII po bezopasnosti rabot v ugolnoy promyshlennosti = Bulletin of VostNII scientific center on safety of work in the coal industry. 2017. № 3. pp. 30–35. (In Russ.).
  7. Yang D., Chen Y., Tang J., Tang Q., Li X., Jiang C., Wang C., Zhang C. Experimental research into the relationship between initial gas release and coal-gas outbursts. Journal of Natural Gas Science and Engineering. 2018. Vol. 50. pp. 157–165.
  8. Jiang C., Xu L., Li X., Tang J., Chen Y., Tian S., Liu H. Identification model and indicator of outburst-prone coal seam. International Journal of Rock Mechanics and Rock Engineering. 2015. Vol. 48. pp. 409–415.
  9. Yin G.Z., Jiang C.B., Wang J.G., Xu J., Zhang D.M., Huang G. A new experimental apparatus for coal and gas outburst simulation. International Journal of Rock Mechanics and Mining Sciences. 2016. Vol. 49. pp. 2005–2013.
  10. Zhao B., Wen G., Sun H., Sun D., Yang H., Cao J., Dai L., Wang B. Similarity criteria and coal-like material in coal and gas outburst physical simulation. International Journal of Coal Science & Technology. 2018. Vol. 5. Iss. 2. pp. 167–178.
  11. Fisenko G.L. Limit conditions of rocks around the workings. M.: Nedra, 1976. 272 p. (In Russ.).
  12. Cherdantsev N.V., Cherdantsev S.V. Analysis of the state of the coal-bearing massif hosting the in-seam working and geological disturbance. Izvestiya RAN. Mekhanika tverdogo tela = Bulletin of the Russian Academy of Sciences. Solid mechanics. 2018. № 2. pp. 110–121. (In Russ.).
  13. Cherdantsev N.V. On Some Conditions for Occurrence of Ultimate Limit State of the Coal Seam Roof at its Development by the Room. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2017. № 5. pp. 17–23. (In Russ.). DOI: 10.24000/0409-2961-2017-5-17-23
  14. Sokolovskiy V.V. Flowing medium statistics. Moscow: Nauka, 1990. 272 p. (In Russ.).
  15. Khristianovich S.A. Continuum mechanics. Moscow: Nauka, 1981. 484 p. (In Russ.).
  16. Cherdantsev N.V. Effect of Methane Pore Pressure on the Geomechanical State of Massif in the Vicinity of the In-seam Working. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2018. № 10. pp. 7–13. (In Russ.). DOI: 10.24000/0409-2961-2018-10-7-13
  17. 17. Cherdantsev N.V. The Results of the Numerical Solution of the Equations of the Limit State of the Seam Marginal Zone and their Approximation by the Polynoms. Bezopasnost truda v promyshlennosti = Occupational Safety in Industry. 2019. № 6. pp. 7–13. (In Russ.). DOI: 10.24000/0409-2961-2019-6-7-13
DOI: 10.24000/0409-2961-2019-8-13-18
Year: 2019
Issue num: August
Keywords : coal-rock massif in-seam working extreme stressed zones resistance characteristics marginal tasks of the limit state gas-bearing coal seam
Authors:
  • Cherdantsev N.V.
    Cherdantsev N.V.
    Dr. Sci. (Eng.), Chief Research Associate, nvch2014@yandex.ru Federal Research Centre of Coal and Coal Chemistry of SO RAN, Kemerovo, Russia