3D Modeling of Stability and Deformation of Reinforced and Unreinforced Face in the Shallow Tunnel

Document Type : Original Article

Authors

1 Young Researchers and Elite Club, South Tehran Branch, Islamic Azad University, Tehran, Iran

2 Department of Civil Engineering, Islamic Azad University Islamshahr Branch, Tehran, Iran.

10.22091/cer.2020.4950.1182

Abstract

Utilizing of fiberglass nail in the face of tunnel is one of the economical and effective pre-support methods for increasing stability and control of settlement in weak grounds and tunnels with extended level and increase of ground mechanical strength. In this study, by taking advantage of 3D modeling of fiberglass nail which is effective in reduction of deformation, settlement, the direct modeling of nail in the 3D finite element and material with equivalent section. This study has covered effects of nail density, the overburden to depth of tunnel ratio. The method of strength reduction for analyzing the safety factor of tunnel has been considered. The result of 3D numerical analysis with limit equilibrium methods (LEM) for determining safety factor has been compared. The comparison of LEM and finite element method revealed that using of nail fiberglass and increases the range of safety factor between 5% to 75% and 1.25 to 2 in terms of overburden to diameter ratio. This increase of nail is dependent on density and overburden. While, with increase to advance length, the amount of vertical displacement would rise in both method, although these measures have no effects in horizontal displacement. In addition to that, using of nail in the tunnel face has caused the amount of vertical displacement between 20 to 35 percent and in the horizontal displacement between 50 to 60 percent of decrease has happened.

Keywords

Main Subjects


[1] Elyasi, A., Javadi, M., Moradi, T., Moharrami, S., Parnian, S., & Amrac, M. (2016). “Numerical modeling of an umbrella arch as a pre-support system in difficult geological conditions: a case study”, Bull Eng Geol Envi-ron, 75(1), 211-221.
[2] Taromi, M., Eftekhari, A., Khademi Hamidi, J., & Aalianvari, A. (2017). “A discrepancy between observed and predicted NATM tunnel behaviors and updating: a case study of the Sabzkuh tunnel”, Bulletin of Engi-neering Geology and the Environment, 76(2), 713–729.
[3] Taromi, M., Eftekhari, A., Khademi Hamidi, J., & Eghbali, A. (2018). “Tunnel designing and construction process in difficult ground conditions using Controlled Deformations (ADECO) approach; a Case Study”, IJMGE, 52(2), 149-160.
[4] Mikaeil, R., Ataei, M., Sereshki, F., & Jafarpour, A. (2019). “Evaluation of the Environmental Impacts of Groundwater Levels Drop Due to the Excava-tion of Large-Scale Tunnels (Case Study: Kouhin Rail-Way Tun-nel) ”, Journal of Civil and Environmental Research, 5(1), 89-103.
[5] Alaghaa, A. S., & Chapmanb, D. N. (2019). “Numerical modelling of tunnel face stability in homogeneous and layered soft ground”, Tunnelling and Underground Space Technology, 94, 103096.
[6] Shiau, J., & Al-Asadi, F. (2020). “Two-dimensional tunnel heading stability factors Fc, Fs and Fγ”, Tunnel-ling and Underground Space Technology, 97, 103293.
[7] Liua, K., Lia, Sh., Dinga, W., Houa, M., Gongc, Y., & Lic, H. (2020). “Pre-supporting mechanism and sup-porting scheme design for advanced small pipes in the silty clay layer”, Tunnelling and Underground Space Technology, 98, 103259.
[8] Chen, S.L., Lee, Ch. Sh., & Wei, Y.S. (2016). “Numerical Analysis of Ground Surface Settlement Induced by Double-O Tube Shield Tunneling”, Journal of Performance of Constructed Facilities, 30(5), 04016012.
[9] Zhao, Ch., Alimardani Lavasan, A., Barciaga, Th., Zarev, V., Datcheva, M., & Schanz, T. (2015). “Model validation and calibration via back analysis for mechanized tunnel simulations– The Western Scheldt tunnel case”, Computers and Geotechnics, 69, 601–614.
[10] Sterpi, D., Rizzo, F., Renda, D., Aguglia, F., Carla, L., & Zenti, e. (2013). “Soil nailing at the tunnel face in difficult conditions: A case study”, Tunnelling and Underground Space Technology, 38, 129–139.
[11] Janin, J. P., Dias, D., Emeriault, F., Kastner, R., Le Bissonnais, H., & Guilloux, A. (2015). “Numerical back-analysis of the southern Toulon tunnel measurements: A comparison of 3D and 2D approaches”, Engineering Geology, 195, 42–52.
[12] Jin, D., Yuan, D., Li, X., & Zheng, H. (2018). “An in-tunnel grouting protection method for excavating twin tunnels beneath an existing tunnel”, Tunnelling and Underground Space Technology, 71, 27-35.
[13] Lunardi, P. (2008). Design and construction of tunnels: Analysis of Controlled Deformations in Rock and Soils (ADECO-RS). Springer Science & Business Media.
[14] Hernándeza, Y. Z., Farfána, A. D., & Pacheco de Assis, A. (2019). “Three-dimensional analysis of excava-tion face stability of shallow tunnels”, Tunnelling and Underground Space Technology, 92, 103062.
[15] Tonon, F. (2010). “Sequential Excavation, NATM and ADECO: What They Have in Common and How They Differ”, Tunnelling and Underground Space Technology, 25, 245–265.
[16] Schweiger, H. F., & Mayer, P. M. (2004). “Fe-analysis of reinforced tunnel face”, Felsbau, 22(4), 47–51.
[17] Pan, Q., Dias, D. (2017), “Upper-bound analysis on the face stability of a non-circular tunnel”, Tunnelling and Underground Space Technology, 62, 96-102.
[18] Peila, D. (1994). “A theoretical study of reinforcement influence on the stability of a tunnel face”, Ge-otechnical and Geological Engineering, 12(3), 145- 168.
[19] Grasso, P., Mahtab, A., & Pelizza, S. (1989). “Riqualificazione della massa rocciosa: un criterio per la stabi-lizzazione di gallerie”, Gallerie e grandi opere sotterraneo, 29, 35–41.
[20] Ruse, N. M. (2004). Räumliche Betrachtung der Standsicherheit der Ortsbrust beim Tunnelvortrieb (Vol. 51). Institut für Geotechnik.
[21] Paternesi, A., Schweiger, H. F., & Scarpellia, G. (2017). “Numerical analyses of stability and deformation behavior of reinforced and unreinforced tunnel faces”, Computers and Geotechnics, 88, 256–266.
[22] Semprich, S. (1980). “Berechnung der Spannungen und Verformungen im Bereich der Ortsbrust von Tun-nelbauwerken in Fels”, Report of the Inst. of Geotech. Engng of the RWTH Aachen, Report No. 8, ISSN 0341-7956.
[23] Baumann, T., Sternath, R., & Schwarz, J. (1997). “Face stability of tunnels in soft rock – Possibilities for the computational analysis”, International Conference on Soil Mechanics and FOundation Engineering, 3, 1389-1392.
[24] Yasitli, N. E. (2013). “Numerical modeling of surface settlements at the transition zone excavated by New Austrian Tunneling Method and Umbrella Arch Method in weak rock”, Arabian journal of geosciences, 6(7), 2699–2708.
[25] Schanz, T., Vermeer, P.A., & Bonnier, P.G. (1999), The hardening-soil model: formulation and veriļ¬cation. In: Brinkgreve, R.B.J. (Ed.), Beyond 2000 in computational geotechnics. Balkema, Rotterdam, 281–290.
[26] Nemati Hayati, A., Ahmadi, M. M., Hajjar, M., & Kashighandi, A. (2012), “Unsupported advance length in tunnels constructed using New Austrian Tunnelling Method and ground surface settlement”, International Journal for Numerical and Analytical Methods in Geomechanics, 37(14), 2170-2185.
[27] Brinkgreeve, R.B.J., Engin, E., & Swolfs, W.M. (2012). Plaxis 2D version 2012 manual, Delft the Nether-lands.
[28] PLAXIS. (2006). “Plaxis user manual (version 8.6)”. Delft University of Technology & Plaxis BV, The Netherlands.
CAPTCHA Image