Damage zone propagation and support pressure estimation around two access tunnels of the Barapukuria coalmine in Bangladesh: a two-dimensional numerical modeling approach

  • Abstract
  • Keywords
  • References
  • PDF
  • Abstract

    The present study uses a two-dimensional boundary element method (BEM) numerical analysis to predict damage zone propagation associated with the required support pressure estimation around the two access tunnels of Barapukuria coalmine in northwest Bangladesh. Two tunnels at different depths are presented here. The stability of the two tunnels that was driven through the weak rocks' strata of Gondwana formation is examined at depths below the surface 290 m and 453 m. The two tunnels involve horseshoe-shaped design. The shallower tunnels, which are located below the surface 290 m, are presented by model A. The deeper tunnels, which are located below the surface 453 m, are presented by model B. Both tunnels are horseshoe-shaped with a height and span of about 4.5 m and 4 m, respectively. The modeling analysis was carried out in two stages to predict the damage zone and required support pressure. The first stage considered the model without support installation. The second stage measured the model with non-uniform internal support pressure installation. It is reasonable to mention that prior and subsequent to the support pressure estimation, three important parameters, like- strength factor, failure trajectories, and deformation boundaries in the vicinity of the two tunnels have been computed properly. Final results reveal that the strength factor values ranged from 0.33 to 0.99 would create the intense deformation at the roof and sidewalls. The damage zone would be extended from 0.64 to 0.74 m towards the roof and sidewalls. The damage zone would be ranged from 1.95 to 2.21 m, for shallower and deeper tunnels, respectively. For shallower tunnels, the required support pressure would be ranged from 4.0 to 9.0 MPa. For deeper tunnels, the essential support pressure would be ranged from 7.0 to 14 MPa.

  • Keywords

    Boundary Element Method; Access Tunnel; Barapukuria Coalmine; Bangladesh.

  • References

      [1] Bobet, A., 2009. Elastic Solution for Deep Tunnels. Application to Excavation Damage Zone and Rockbolt Support. Rock Mechanics and Rock En-gineering 42(2), 147–174. http://dx.doi.org/10.1007/s00603-007-0140-0.

      [2] Ellis, D., 2005. High standards in Heatrow's art. Tunnels and Tunneling Inter-national 37(9), 29–34.

      [3] Hoek, E., 1998. Tunnel support in weak rock. Proc. Reg. Keynote address, Symposium of Sedimentary Rock Engineering, Taipei, Taiwan, No-vember 20-22, pp.1–12.

      [4] Islam, M. R and Hayashi, D., 2008. Geology and coal bed methane resource potential of the Gondwana Barapukuria Coal Basin, Dinajpur, Bangla-desh. International Journal of Coal Geology 75, 127–143. http://dx.doi.org/10.1016/j.coal.2008.05.008.

      [5] Islam, M.R., Hayashi, D., Kamruzzaman, A.B.M., 2009. Finite element modeling of stress distributions and problems for multi-slice longwall mining in Bangladesh, with special reference to the Barapukuria coal mine. International Journal of Coal Geology 78(2), 91–109. http://dx.doi.org/10.1016/j.coal.2008.10.006.

      [6] Islam, M.R., and Shinjo, R., 2009a. Mining-induced fault reactivation associated with the main conveyor belt roadway and safety of the Barapukuria Coal Mine in Bangladesh: Constraints from BEM simulations. International Journal of Coal Geology 79(4), 115-130. http://dx.doi.org/10.1016/j.coal.2009.06.007.

      [7] Islam, M.R., and Shinjo, R., 2009b. Numerical simulation of stress distributions and displacements around an entry roadway with igneous intrusion and potential sources of seam gas emission of the Barapukuria coal mine, NW Bangladesh. International Journal of Coal Geology 78(4), 249 –262. http://dx.doi.org/10.1016/j.coal.2009.03.001.

      [8] Islam, M.R., and Faruque, M.O., 2012. Numerical modeling of slope stability consideration of an open-pit coalmine in the Phulbari coal basin, NW Bangladesh. Electronic Journal of Geotechnical Engineering (EJGE) 17(y): 3717-3729.

      [9] Karakus, M., Fowell, R.J., 2003. Effects of different tunnel face advance exca-vation on the settlement by FEM. Tunneling and Underground Space Technology 18(5), 513–523. http://dx.doi.org/10.1016/S0886-7798(03)00068-3.

      [10] Minguez, F., Gregory, A., Guglielmetti, V., 2005. Best practice in EPB man-agement, Tunnels and Tunneling International 37, 21–25.

      [11] Ocak, I., 2009. Environmental effects of tunnel excavation in soft and shallow ground with EPBM: the case of Istanbul. Environmental Earth Scienc-es 59(2), 347–352. http://dx.doi.org/10.1007/s12665-009-0032-6.

      [12] Suwansawat, S., Einstein, H. H., 2006. Artificial neural networks for pre-dicting the maximum surface settlement caused by EPB shield tunneling. Tunneling and Underground Space Technology 21(2), 133–150. http://dx.doi.org/10.1016/j.tust.2005.06.007.

      [13] Tan, W.L., Ranjit, P.G., 2003. Parameters and considerations in soft ground tunneling, Electronics Journal of Geotechnical Engineering 8(D), ppr0344_3.

      [14] Wardell Armstrong, 1991, Techno-Economic Feasibility Study of Barapukuria Coal Project (unpubl.), Dinajpur, Bangladesh.

      [15] Yavuz, H., 2006. Support pressure estimation for circular and non-circular openings based on a parametric numerical modelling study. The jour-nal of the South African Institute of Mining and Metallurgy 106(2), 129-138.




Article ID: 4865
DOI: 10.14419/ijag.v3i2.4865

Copyright © 2012-2015 Science Publishing Corporation Inc. All rights reserved.