Cross Section Effects on Convergence-Confinement Method in Multi Stage Tunnel Excavation

Document Type : Regular Paper

Authors

1 Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Civil Engineering, Bu-Ali Sina University, Hamedan, Iran

Abstract

Dimensionless coefficient (l) in convergence confinement method indicates the relaxation of stress in the wall of the tunnel at different excavation movements. This factor is  contemplated a constant number in previous studies and tunnel geometric characteristics (such as depth, cross-section shape, radius, soil material, etc.) are not included in its determination; however, ignoring these effects can cause significant errors in the analysis of tunnels. In this article, the effect of excavation pattern and tunnel cross section shape on stress reduction factor  is investigated. For this purpose, at first, by considering the conventional cross sections of the tunnel (circular, horseshoe, and double arch), applying finite difference numerical simulation software FLAC 2D and FLAC 3D, the type of excavation (full face and multi face) was inspected in estimating the stress reduction factor by considering depth, radius, and dissimilar points around the tunnel. At last, studies were carried out between the 2D and 3D analyses and the experiments conducted at Karaj Subway to verify the results obtained from the above 2D analyses. The results of this study indicate the significant effect of radius, depth, point position around tunnel cross-section and its shape on stress reduction factor. Convergence around tunnel variation was observed about 21 percent in horseshoe tunnel. However, the maximum and minimum convergence value was in circle and double arch respectively in a constant radius and depth. The results illustrate the variety percentage error in tunnel wall about 27, 10 and 7 percent for circle, double arch and horseshoe respectively. Nonetheless, percentage error was decreased by increasing the tunnel radius. Applying variable stress reduction factor in the all-around of tunnel cross section can lead to more realistic simulations of complex behavior of tunnels during the excavation. Moreover, this method can be utilized for the analysis and design of tunnel due to its time saving nature and at the same time sufficient accuracy.

Keywords

Main Subjects

References

[1] Vu, T. M., Sulem, J., Subrin, D., & Monin, N. (2012). Semi-Analytical Solution for Stresses and Displacements in a Tunnel Excavated in Transversely Isotropic Formation with Non-Linear Behavior. Rock Mechanics and Rock Engineering, 46(2), 213-229.
[2] Koukoutas, S. P., & Sofianos, A. I. (2015). Settlements Due to Single and Twin Tube Urban EPB Shield Tunnelling. Geotechnical and Geological Engineering, 33(3), 487-510.
[3] Do, N.-A., Dias, D., Oreste, P., & Djeran-Maigre, I. (2013). 2D Tunnel Numerical Investigation: The Influence of the Simplified Excavation Method on Tunnel Behaviour. Geotechnical and Geological Engineering, 32(1), 43-58.
[4] Zhang, Z, Zhang, M, Jiang, Y, Bai, Q, Zhao, Q. (2017) Analytical prediction for ground movements and liner internal forces induced by shallow tunnels considering non-uniform convergence pattern and ground-liner interaction mechanism, Soils and Foundations 57, 211-226.
[5] Xie, X, Yang, Y, Ji, M. (2016). Analysis of ground surface settlement induced by the construction of a large-diameter shield-driven tunnel in Shanghai, China. Tunnelling and Underground Space Technology 51, 120–132.
[6] Ghotbi Ravandi, E., & Rahmannejad, R. (2013). Wall displacement prediction of circular, D shaped and modified horseshoe tunnels in non-hydrostatic stress fields. Tunnelling and Underground Space Technology, 34, 54-60.
[7] Gschwandtner, G. G., & Galler, R. (2012). [7] Input to the application of the convergence confinement method with time-dependent material behaviour of the support. Tunnelling and Underground Space Technology, 27(1), 13-22.
[8] Maleki, M., & Mousivand, M. (2014). Safety evaluation of shallow tunnel based on elastoplastic-viscoplastic analysis. Scientia Iranica. Transaction A, Civil Engineering 21 (5), 1480.
[9] Alejano, L. R., Rodriguez-Dono, A., Alonso, E., & Fdez.-Manín, G. (2009). Ground reaction curves for tunnels excavated in different quality rock masses showing several types of post-failure behaviour. Tunnelling and Underground Space Technology, 24(6), 689-705.
[10] Cai, Y., Jiang, Y., Djamaluddin, I., Iura, T., & Esaki, T. (2015). An analytical model considering interaction behavior of grouted rock bolts for convergence–confinement method in tunneling design. International Journal of Rock Mechanics and Mining Sciences, 76, 112-126.
[11] Chen, R., & Tonon, F. (2010). Closed-Form Solutions for a Circular Tunnel in Elastic-Brittle-Plastic Ground with the Original and Generalized Hoek–Brown Failure Criteria. Rock Mechanics and Rock Engineering, 44(2), 169-178.
[12] Fang, Q., Zhang, D., Zhou, P., & Wong, L. N. Y. (2013). Ground reaction curves for deep circular tunnels considering the effect of ground reinforcement. International Journal of Rock Mechanics and Mining Sciences, 60, 401-412.
[13] Cui, L., Zheng, J.-J., Zhang, R.-J., & Lai, H.-J. (2015). A numerical procedure for the fictitious support pressure in the application of the convergence–confinement method for circular tunnel design. International Journal of Rock Mechanics and Mining Sciences, 78, 336-349.
[14] Do, N.-A., Dias, D., & Oreste, P. (2014). Three-dimensional numerical simulation of mechanized twin stacked tunnels in soft ground. Journal of Zhejiang University SCIENCE A, 15(11), 896-913.
[15] Houhou, M. N., Emeriault, F., & Vanoudheusden, É. (2016). Three-Dimensional Back-Analysis of an Instrumented Shallow Tunnel Excavated by a Conventional Method. Geotechnical and Geological Engineering.
[16] Vlachopoulos, N., & Diederichs, M. S. (2014). Appropriate Uses and Practical Limitations of 2D Numerical Analysis of Tunnels and Tunnel Support Response. Geotechnical and Geological Engineering, 32(2), 469-488.
[17] Bloodworth, A. (2002). Three-dimensional analysis of tunneling effects on structures to develop design methods. (Ph.D. Thesis), Oxford University, UK, UK.
[18] Burd, H., Houslby, G., Augarde, C., & Liu, G. (2000). Modelling tunnelling-induced settlement of masonry buildings. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 143(1), 17-30.
[19] Ng, C., Simons, N., & Menzies, B. (2004). A short course in soil-structure engineering of deep foundations, excavations and tunnels: . Thomas Telford Services Limited.
[20] Ng, C. W., & Lee, G. T. (2005). Three-dimensional ground settlements and stress-transfer mechanisms due to open-face tunnelling. Canadian Geotechnical Journal, 42(4), 1015-1029.
[21] Karakus, M. (2007). Appraising the methods accounting for 3D tunnelling effects in 2D plane strain FE analysis. Tunnelling and Underground Space Technology, 22(1), 47-56.
[22] Rowe, R., Lo, K., & Kack, G. (1983). A method of estimating surface settlement above tunnels constructed in soft ground. Canadian Geotechnical Journal, 20(1), 11-22.
[23] Carranza-Torres, C., & Fairhurst, C. (2000). Application of the convergence-confinement method of tunnel design to rock masses that satisfy the Hoek-Brown failure criterion. Tunnelling and Underground Space Technology, 15(2), 187-213.
[24] Dias, D. (2011). Convergence-confinement approach for designing tunnel face reinforcement by horizontal bolting. Tunnelling and Underground Space Technology, 26(4), 517-523.
[25] González-Nicieza, C., Álvarez-Vigil, A. E., Menéndez-Díaz, A., & González-Palacio, C. (2008). Influence of the depth and shape of a tunnel in the application of the convergence–confinement method. Tunnelling and Underground Space Technology, 23(1), 25-37.
[26] Mahdevari, S., & Torabi, S. R. (2012). Prediction of tunnel convergence using Artificial Neural Networks. Tunnelling and Underground Space Technology, 28, 218-228.
[27] Panet, M. (2001). Recommendations on the convergence-confinement method. AFTES report, Version, 1, 1-11.
[28] Sadeghiyan, R., Hashemi, M., & Moloudi, E. (2016). Determination of longitudinal convergence profile considering effect of soil strength parameters. International Journal of Rock Mechanics and Mining Sciences, 82, 10-21.
[29] Potts, D. (1977). Behavior of Lined and Unlined Tunnels in Sand. (Ph.D. Thesis), Cambridge University, UK, UK.  
[30] Swoboda, G. (1979). Finite element analysis of the new austrian tunnelling method (NATM). Paper presented at the Proceedings of the 3rd International Conference on Numerical Methods in Geomechanics, Aachen.
[31] Swoboda, G., Marence, M., & Mader, I. (1994). Finite element modelling of tunnel excavation. International Journal of Engineering Modelling, 6, 51-63.
[32] Schikora, K., & Ostermeier, B. (1988). Two-dimensional calculation model in tunneling-verification by measurement results and by spatial calculation. Paper presented at the Sixth international conference on numerical methods in geomechanics, Innsbruck, Austria.
[33] Mousivand, M; Maleki, M; Nekooei, M; Mansoori, M.R. (2017). Application of Convergence–Confinement Method in Analysis of Shallow Non-circular Tunnels, Geotechnical and Geological Engineering, 1-14
[34] Darya Khak Pey consulting engineering, (2005). The final report of geotechnical studies of the approved rout of the Karaj subway second part.
[35] Addenbrooke, T., & Potts, D. (2001). Twin tunnel interaction: surface and subsurface effects. International Journal of Geomechanics, 1(2), 249-271.
[36] Mousivand, M. (2016). Assessment of convergence-confinement method on shallow tunnels in soft ground. (Ph.D These), Science and research branch, Islamic Azad University, Tehran, Iran, 250.

Files

History

  • Receive Date: 29 August 2017
  • Revise Date: 17 October 2017
  • Accept Date: 31 October 2017

Share

How to cite

Statistics