Practical Method for the Design of Pretensioned Fully Grouted Rockbolts in Tunnels
Publication: International Journal of Geomechanics
Volume 16, Issue 1
Abstract
This study develops an analytical approach to quantitatively model the efficiency of the pretensioning of grouted rockbolts in terms of reduction of tunnel convergence. In this study, the distribution of force along the pretensioned fully grouted bolt is calculated by the assumption of a rigid connection between the bolt and the rock mass. A compressive force is then applied to the bolt head on the tunnel surface to consider the shear relative displacement between the bolt and the rock mass. The magnitude of this compressive force is found by modeling the bolt boundaries’ stiffness. The theoretical proposed approach is simplified to be used for practical purposes. The results show that if the stiff end plate is tightened to the bolt head (complete planner contact), the grouting effect of the pretensioned fully grouted bolts on tunnel stability can be neglected.
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References
Aydan, Ö. (1989). “The stabilisation of rock engineering structures by rockbolts.” Ph.D. thesis, Queens’s Univ., Kingston, Ontario.
Bischoff, J. A., and Smart, J. D. (1975). “A method of computing a rock reinforcement system which is structurally equivalent to an internal support system.” Proc., 16th Symp. on Rock Mechanics, Univ. of Minnesota, Minneapolis, 179–184.
Bobet, A. (2006). “A simple method for analysis of point anchored rockbolts in circular tunnels in elastic ground.” Rock Mech. Rock Eng., 39(4), 315–338.
Bobet, A., and Einstein, E. (2011). “Tunnel reinforcement with rockbolts.” Tunnel. Underground Space Tech., 26(1), 100–123.
Brown, E. T., Bray, J. W., Ladanyi, B., and Hoek, E. (1983). “Ground response curves for rock tunnels.” J. Geotech. Engrg., 15–39.
Cai, Y., Esaki, T., and Jiang, Y. (2004a). “An analytical model to predict axial load in grouted rock bolt for soft rock tunneling.” Tunnel. Underground Space Tech., 19(6), 607–618.
Cai, Y., Jiang, Y. J., and Esaki, T. (2004b). “A rock bolt and rock mass interaction model.” Int. J. Rock Mech. Mining Sci., 41(7), 1055–1067.
Carranza-Torres, C. (2009). “Analytical and numerical study of the mechanics of rockbolt reinforcement around tunnels in rock masses.” Rock Mech. Rock Eng., 42(2), 175–228.
Fahimifar, A., and Ranjbarnia, M. (2009). “Analytical approach for the design of active grouted rockbolts in tunnel stability based on convergence-confinement method.” Tunnel. Underground Space Tech., 24(4), 363–375.
Fahimifar, A., and Soroush, H. (2005). “A theoretical approach for analysis of the interaction between grouted rockbolts and rock masses.” Tunnel. Underground Space Tech., 20(4), 333–343.
Freeman, T. J. (1978). “The behavior of fully-bonded rock bolts in the kielder experimental tunnel.” Tunnels Tunnel., 10(5), 37–40.
Grasso, P. G., Mahtab, A., and Pelizza, S. (1989). “Riqualificazione della massa roccoisa: Un criterio per la stabilizzaazione della gallerie.” Gallerie e Grandi Opere Sotterranee, 29(38), 35–41 (in Italian).
Guan, Zh., Jiang, Y., Tanabasi, Y., and Huang, H. (2007). “Reinforcement mechanics of passive bolts in conventional tunneling.” Int. J. Rock Mech. Mining Sci., 44(4), 625–636.
Hoek, E., and Brown, E. T. (1980). Underground excavations in rock. The Institution of Mining and Metallurgy, London.
Huang, Z., Broch, E., and Lu, M. (2002). “Cavern roof stability—mechanism of arching and stabilization by rockbolting.” Tunnel. Underground Space Tech., 17(3), 249–261.
Indraratna, B., and Kaiser, P. K. (1990a). “Design of grouted rock bolts based on the convergence control method.” Int. J. Rock Mech. Mining Sci. Geomech., 27(4), 269–281.
Indraratna, B., and Kaiser, P. K. (1990b). “Analytical model for the design of grouted rock bolts.” Int. J. Numer. Anal. Meth. Geomech., 14, 227–251.
Li, C., and Stillborg, B. (1999). “Analytical models for rock bolts.” Int. J. Rock Mech. Mining Sci., 36(8), 1013–1029.
Oreste, P. P. (2008). “Distinct analysis of fully grouted bolts around a circular tunnel considering the congruence of displacements between the bar and the rock.” Int. J. Rock Mech. Mining Sci., 45(7), 1052–1067.
Oreste, P. P., and Peila, D. (1996). “Radial passive rockbolting in tunneling design with a new convergence-confinement model.” Int. J. Rock Mech. Mining Sci. Geomech., 33(5), 443–454.
Osgoui, R. R., and Oreste, P. (2010). “Elasto-plastic analytical model for the design of grouted bolts in a hoek–brown medium.” Int. J. Numer. Anal. Meth. Geomech., 34(16), 1651–1686.
Peila, D., and Oreste P. P. (1995). “Axisymmetric analysis of ground reinforcing in tunneling design.” Comput. Geomach., 17(2), 253–274.
Ranjbarnia, M., (2014). “Theoretical analysis of pre-tensioned grouted rockbolts behavior in tunnels considering the interaction of bolt, grout, and rock mass.” Ph.D. thesis, Dept. Civil and Environmental Engineering, Amirkabir Univ. of Technology, Tehran, Iran.
Ranjbarnia, M., Fahimifar, A., and Oreste, P. (2014). “A simplified model to study the behavior of pre-tensioned fully grouted bolts around tunnels and to analyze the more important influencing parameters.” J. Mining Sci., 50(3), 533–548.
Stille, H., Holmberg, M., and Nord G. (1989). “Support of weak rock with grouted bolts and shotcrete.” Int. J. Rock Mech. Mining Sci. Geomech., 26(1), 99–113.
Ward, W. H., Coats, D. J., and Tedd, P. (1976). “Performance of support systems in the four fathom mudstone.” Proc., Tunnelling 76, Building Research Establishment, London, 329–340.
Information & Authors
Information
Published In
International Journal of Geomechanics
Volume 16 • Issue 1 • February 2016
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Mar 28, 2014
Accepted: Oct 28, 2014
Published online: Apr 30, 2015
Discussion open until: Sep 30, 2015
Published in print: Feb 1, 2016
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