The Effect of Weight of Plastic Zone on Distribution of Stresses and Radial Displacement around a Tunnel

Document Type : Research Paper

Authors

1 Ph.D. Candidate in the Department of railway at Iran University of Science and Technology

2 Amirkabir University of Technology

Abstract

With starting plastic deformation around the tunnel, the pressure on the tunnel roof increases due to the weight of the plastic area, which influences on the tunnel stability. In this paper, with considering strain-softening rock mass around the tunnel and plastic region weight and using the generalized Hook-Brown failure criterion, the stress and displacement equations around the tunnel were rewritten and solved by the semi-analytical method. The results show that considering the weight of the plastic region caused the distribution of stress around the tunnel are changed and the amount of displacement and radius of the plastic region increases. This becomes more importance in conditions with larger plastic radius. Also, by investigation of the effect of Hook-Brown criterion parameters on the displacement around the tunnel, the importance of each of the parameters is shown. The results show that Hook-Brown parameters in plastic condition have a greater effect on the displacement around the tunnel than in peak conditions.

Keywords

References

Alejano, L. R. and Alonso, E. 2005. “Considerations of the dilatancy angle in rocks and rock masses”. Int. J. Rock Mech.Min Sci., 42: 481-507.
Alejano, L. R., Rodriguez-Dono, A., Alonso, E. and  Fdez.-Manín, G. “Ground reaction curves for tunnels excavated in different quality rock masses showing several types of post-failure behaviour”. Tunn. Undergr. Sp. Tech., 24: 689-705.
Alonso, E., Alejano, L. R. and Varas, F. “Ground response curves for rock masses exhibiting strain-softening behavior”. Int. J. Num. Anal. Meth. Geomech., 27: 1153-1185.
Carranza-Torres, C. and Fairhurest, C. 1999. “The elasto-plastic response of underground excavations in rock masses that satisfy the Hoek-Brown failure criterion”. Int. J. Rock Mech. Min Sci., 36: 777-809.
Carranza-Torres , C. and Fairhurst, C. 2000. “Application of the convergence-confinement method of tunnel design to rock masses that satisfy the Hoek-Brown failure criterion”. Tunn. Undergr. Sp. Tech., 15: 187-213.
Carranza-Torres, C. 2004. “Elasto-plastic solution of tunnel problems using the generalized form of the Hoek-Brown failure criterion”. Int. J. Rock Mech. Min Sci., 41: 1-11.
Detournay, E. 1986. “Elastoplastic model of a deep tunnel for a rock with variable dilatancy”. Rock Mech. Rock Eng., 19: 99-108.
Hoek, E. and Brown, E. T. 1980. “Underground excavations in rock”. The Institution of Mining and Metallurgy, London.
Jaeger, J. C., Cook, N. G. W. and R. W. Zimmerman. 1976. “Fundamentals of rock mechanics”. Chapman and Hall.
Lee, Y. K. and Pietruszczak, S. 2007. “A new numerical procedure for elasto-plastic analysis of a circular opening excavated in a strain-softening rock mass”. Tunn. Undergr. Sp. Tech., 23: 588-599.
Malvern, L. 1969. “Introduction to the mechanics of a continuous medium”. Prentice-Hall, New Jersey.
Panet, M. 1995. “Le Calcul Des Tunnels Par La Méthode Convergence-Confinement”. Presses ENPC, Paris.
Park, K. H., Tontavanich, B. and Lee, J. G. 2008. “A simple procedure for ground response curve of circular tunnel in elastic-strain softening rock masses”. Tunnl. Undergr. Sp. Tech., 23(2): 151-159.
Sharan, S. 2005. “Exact and approximate solutions for displacements around circular openings in elastic-brittle-plastic Hoek-Brown rock”. Int. J. Rock Mech. Min. Sci., 42: 542-549.
Sharan, S. 2008. “Analytical solutions for stresses and displacements around a circular opening in a generalized Hoek-Brown rock”. Int. J. Rock Mech. Min. Sci., 45: 78-85.
Sofianos, A. 2009. “Tunneling Mohr-Coulomb strength parameters for rock masses satisfaying the generalized Hoek-Brown criterion”. Int. J. Rock Mech. Min. Sci., 40: 435-440.
Wang, Y.  1996. “Ground response of circular tunnel in poorly consolidated rock”. ASCE, J. Geotech. Eng., 9: 703-708.
Zareifard, M. R. and Fahimifar, A. 2012. “A new solution for shallow and deep tunnels by considering the gravitational loads”. Acta Geotech. Slov., 2: 37-49.

Files

History

  • Receive Date: 15 June 2017
  • Revise Date: 18 February 2018
  • Accept Date: 23 February 2018

Share

How to cite

Statistics