Surface Buildings Risk Classification and Evaluation of In-Situ Piles Effect in Mitigation the Settlements Caused By Excavation of Metro Tunnels in Urban Areas (Case Study: Tabriz Metro)

Document Type : Research Paper

Authors

1 civil engineering department, faculty of engineering, Azarbaijan Shahid Madani university

2 Master student, civil engineering department, Azarbaijan Shahid Madani university

Abstract

Fast, easy, safe and low cost transportation is the base of progress and economic development. In large cities the cost of land ownership and the improvement of urban structure and environmental problems reduce the possibility of rapid development of surface transportation lines. The need for the construction of underground lines of transport seems to be the right approach. Like all the construction projects, there will be social and technical consequences; perhaps the most important technical effect is the induced surface settlement due to excavation of tunnels and the construction of underground stations on surface buildings. In this numerical study, by using finite element software "plaxis8.6", the risk classification of surface buildings with various story and width are evaluated. Because of considerable effect of tunnel geometry and surrounding soil geotechnical properties on surface settlements, the region near to S4 station of Tabriz metro line 2 adopted as a case study. In this part the tunnel has a low overburden and the width of the street that tunnel route passed under it is low. Considering operational limits, the use of in-situ concrete piles in the vicinity of the surface buildings is choose as a mitigation technique. The length of the pile and their center to center space were matters of interest. Based on obtained results the risk classification of buildings reduce from 3 to 2 category due to construction of piles, which indicates good performance of this technique. Accurate examination of interaction between structure and soil can't be completely defined. Therefore, different methods of modeling the surface structures were applied. The soil behavior was modeled by the Mohr–Coulomb and hardening soil (HS) criterions. Also, with analyses more than 220 model, the effects of tunnel contraction ratio and street width on induced surface settlements and performance of mitigation technique were studied.

Keywords


Bilotta, E. and Russo, G. 2010. “Use of a line of piles to prevent damages induced by tunnel excavation”. J. Geotech. Geoenviron. Eng., 137(3): 254-262.
Boscardin, M. D. and Cording, E. J. 1989. “Building response to excavation-induced settlement”. Journal of Geotechnical Engineering, 115(1): 1-21.
Burland, J.B., Broms, B.B. and DeMello, V.F.B. 1977. “Behaviour of Foundations and Structures”. Proc.: IX ICSMFE. Tokyo, State-of-the-Art Report, Session 2, Vol.2.
Burland, J. B. 1995. “Assessment of risk of damage to buildings due to tunnelling and excavation”. 1st International Conference on Earthquake Geotechnical Engineering, Tokyo.
Di Mariano, A., Gesto, J. M., Gens, A. and Schwarz, H. 2007. “Ground deformation and mitigating measures associated with the excavation of a new metro line”. In: Proc. XIV European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE, pp. 1901-1906.
Fantera, L., Rampello, S. and Masini, L. 2016. “A mitigation technique to reduce ground settlements induced by tunnelling using diaphragm walls”. Proc. Eng., 158: 254-259.
Farrell, R. P. and Mair, R. J. 2010. “Centrifuge modelling of the response of buildings to tunneling”. PP. 549-554. In: Springman, S., Laue, J. and Seward, L. (Eds.), Physical Modelling in Geotechnics, CRC Press.
Franzius, J. N. 2003. “Behavior of buildings due to tunnel induced subsidence”. PhD Thesis, Department of Civil and Environmental Engineering, Imperial College of Science, Technology and Medicine, London, UK.
Gens, A., Di Mariano, A., Gesto, J. M. and Schwarz, H. 2006. “Ground movement control in the construction of a new metro line in Barcelona. In: Geotechnical Aspects of Underground Construction in Soft Ground, Proceedings of the 5th International Symposium TC28, Amsterdam, The Netherlands, 15-17 June, CRC Press.
Guglielmetti, V., Grasso, P., Mahtab, A. and Xu, S. 2008. “Mechanized tunnelling in urban areas: Design methodology and construction control”. CRC Press.
Kitiyodom, P., Matsumoto, T. and Kawaguchi, K. 2005. “A simplified analysis method for piled raft foundations subjected to ground movements induced by tunneling”. Int. J. Numer. Anal. Meth. Geomech., 29(15); 1485-1507.
Lee, Y. J. and Yoo, C. S. 2006. “Behaviour of a bored tunnel adjacent to a line of loaded piles”. Tunn. Undergr. Sp. Tech., 21(3-4): 370.
Loganathan, N., Poulos, H. G. and Xu, K. J. 2001. “Ground and pile-group responses due to tunneling”. Soils Found., 41(1): 57-67.
Mair, R. J., Taylor, R. N. and Burland, J. B. 1996. “Prediction of ground movements and assessment of risk of building damage due to bored tunneling”. In: International Conference of Geotechnical Aspects of Underground Construction in Soft Ground, London, UK, pp. 713-718.
Mroueh, H. and Shahrour, I. 2003. “A full 3-D finite element analysis of tunneling–adjacent structures interaction”. Comp. Geotech., 30(3): 245-253.
Potts, D. M. and Addenbrooke, T. I. 1997. “A structure's influence on tunnelling-induced ground movements”.Proc. Inst. Civ. Eng.: Geotech. Eng., 125(2).
Potts, D. M., Zdravkovic, L. and Zdravković, L. 2001. “Finite element analysis in geotechnical engineering: Application”. Vol. 2, Thomas Telford.
Rankin, W. J. 1988. “Ground movements resulting from urban tunnelling: Predictions and effects”. Geological Society, Engineering Geology Special Publications, London, 5(1): 79-92.
Teo, P. L. and Wong, K. S. 2012. “Application of the hardening soil model in deep excavation analysis”. The IES J., Part A: Civ. Struct. Eng., 5(3): 152-165.
Vahdatirad, M. J., Ghodrat, H., Firouzian, S. and Barari, A. 2010. “Analysis of an underground structure settlement risk due to tunneling-A case study from Tabriz, Iran”. Songklanakarin J. Sci. Technol., 32(2).