Document Type: Original Research Paper


1 Shahrood University of Technology, Faculty of Mining, Geophysics and Petroleum Engineering, Shahrood, Iran

2 Sahand University of Technology, Dept. of Mining Engineering, Tebriz, Iran



Evaluation of the interaction between a new and the existing underground structures is one of the important problems in urban tunneling. In this work, using FLAC3D, four numerical models of single- and twin-tube tunnels in urban areas are developed, where the horizontal distance between the single- and twin-tube tunnels are varied. The aim is to analyze the effects of the horizontal distances, considering various criteria such as the deformation of linings, the forces and moments exerted on the twin-tube tunnels and their safety factors, the subsidence that occur on the surface and the nearby buildings, the stability of the single-tube tunnel, and the stability of the pillar lying between the single- and twin-tube tunnels. Considering the above-mentioned criteria, the results obtained indicate that the interaction between the single- and twin-tube tunnels is virtually negligible in the distance more than three times the single-tube tunnel diameter. Also the stability of the pillar lying between the tunnels makes the distance to be chosen at least 1.5 times the single-tube tunnel diameter.


[1]. Chakeri, H. and Ünver, B. (2014). A new equation for estimating the maximum surface settlement above tunnels excavated in soft ground. Environmental earth sciences. 71 (7): 3195-3210.‏

[2]. Soliman, E., Duddeck, H. and Ahrens, H. (1993). Two-and three-dimensional analysis of closely spaced double-tube tunnels. Tunnelling and Underground Space Technology. 8 (1): 13-18.‏

[3]. Kawata, T., Ohtsuka, M. and Kobayashi, M. (1993). Observational construction of large-scaled twin road tunnels with minimum interval. In Infrastructures souterraines de transports (pp. 241-248).‏

[4]. Perri, G. (1995). Analysis of the effects of the two new twin tunnels excavation very close to a big diameter tunnel of Caracas, subway. In International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts (Vol. 3, No. 32, p. 138A).‏

[5]. Yamaguchi, I., Yamazaki, I. and Kiritani, Y. (1998). Study of ground-tunnel interactions of four shield tunnels driven in close proximity, in relation to design and construction of parallel shield tunnels. Tunnelling and Underground Space Technology. 13 (3): 289-304.‏

[6]. Karakus, M., Ozsan, A. and Başarır, H. (2007). Finite element analysis for the twin metro tunnel constructed in Ankara Clay, Turkey. Bulletin of Engineering Geology and the Environment. 66 (1): 71-79.‏

[7]. Liu, H.Y., Small, J.C., Carter, J.P. and Williams, D.J. (2009). Effects of tunnelling on existing support systems of perpendicularly crossing tunnels. Computers and Geotechnics. 36 (5): 880-894.‏

[8]. Addenbrooke, T.I. and Potts, D.M. (2001). Twin tunnel interaction: surface and subsurface effects. International Journal of Geomechanics. 1 (2): 249-271.‏

[9]. Chehade, F.H. and Shahrour, I. (2008). Numerical analysis of the interaction between twin-tunnels: Influence of the relative position and construction procedure. Tunnelling and Underground Space Technology. 23 (2): 210-214.‏

[10]. Chakeri, H., Hasanpour, R., Hindistan, M.A. and Ünver, B. (2011). Analysis of interaction between tunnels in soft ground by 3D numerical modeling. Bulletin of Engineering Geology and the Environment. 70 (3): 439-448.‏

[11]. Sarfarazi, V., Haeri, H., Safavi, S., Marji, M.F. and Zhu, Z. (2019). Interaction between two neighboring tunnel using PFC2D. Structural Engineering and Mechanics. 71 (1): 77-87.‏

[12]. Abdollahi, M.S., Najafi, M., Bafghi, A.Y. and Marji, M.F. (2019). A 3D numerical model to determine suitable reinforcement strategies for passing TBM through a fault zone, a case study: Safaroud water transmission tunnel, Iran. Tunnelling and Underground Space Technology, 88, 186-199.‏

[13]. Mirsalari, S.E., Fatehi Marji, M., Gholamnejad, J. and Najafi, M. (2017). A boundary element/finite difference analysis of subsidence phenomenon due to underground structures. Journal of Mining and Environment. 8 (2): 237-253.‏

[14]. Lambrughi, A., Rodríguez, L.M. and Castellanza, R. (2012). Development and validation of a 3D numerical model for TBM–EPB mechanised excavations. Computers and Geotechnics, 40, 97-113.‏

[15]. Structurepoint (2012) spColumn Manual. Skokie, USA.

[16]. Carranza-Torres, C. and Diederichs, M. (2009). Mechanical analysis of circular liners with particular reference to composite supports. For example, liners consisting of shotcrete and steel sets. Tunnelling and Underground Space Technology. 24 (5): 506-532.‏

[17]. Sakurai S (1997) Lessons learned from field measurements in tunneling. Tunn Undergr Sp Tech 12 (4): 453-460. doi: 10.1016/S0886-7798(98)00004-2.

[18]. Rankin, W (1988) Ground Movements Resulting from Urban Tunnelling: Predictions and Effects. Geological Society London Engineering Geology Special Publications. 5 (1):79-92. doi: 10.1144/GSL.ENG.1988.005.01.06.

[19]. Guglielmetti, V., Grasso, P., Mahtab, A. and Xu, S. (Eds.). (2008). Mechanized tunnelling in urban areas: design methodology and construction control. CRC Press.‏