Comparative risk analysis of NATM and TBM for mixed-face large-diameter urban tunneling

도심지 대단면 복합지반 NATM 과 TBM 터널공법의 비교위험도 분석

  • Received : 2010.08.31
  • Accepted : 2011.01.10
  • Published : 2011.01.31


The risk assessment is essential for tunnel design in order to minimize risks associated with uncertainty about geological conditions and tunneling method. This paper provides a comparative risk analysis of a large single bore TBM driven tunnel against sequentially excavated NATM tunnel for a mixed-face large-diameter urban tunnel project near or under a river. The focus of this assessment is on the risks associated with the tunnel excavation methods, in particular whether a TBM or NATM presents more or less risk to achieve the planned excavation duration and bring the project within the estimated bid price. First, the impacts and risks to tunnel construction under each method were discussed, and the risks were scored and ranked in the order of perceived severity and likelihood. Finally, the assessment from a risk based perspective was conducted to decide which alternate tunneling method is more likely to deliver the project with the least time and cost. It is very important to note that this study is only applied to this tunnel project with specific geological conditions and other contract requirements.


  1. Barla, G., Pelizza, S. (2000), TBM Tunnelling in Difficult Ground Conditions.
  2. Barton, N. (2000), TBM Tunneling in Jointed and Faulted Rock, Taylor & Francis, p. 184.
  3. Holen, H., Anlegg, S. (1998), TBM vs drill & blast tunnelling, Norwegian TBM Society, pp. 95-98.
  4. Huang, R. (2008), The Shanghai Yangtse River Tunnel: Theory, Design, and Construction, p. 360.
  5. Parsons Brinckerhoff, Inc. (2010), Tunnel Options Risk Assessment for OOO Road Expansion Project.
  6. Samsung C&T (2010a), OOO Road Expansion Project - Geotechnical Investigation Report.
  7. Samsung C&T (2010b), OOO Road Expansion Project - Tunnel Design Report.
  8. Tarkoy, P.J. (1996), "Comparing TBMs with drill and blast excavation", Int'1 J. of Rock Mech. and Mining Sci. and Geomech. Abst., Vol. 33, No. 4, pp. 186A-186A(1).
  9. URS Corporation (2005), OOO Tunnel Project - Qualitative Risk Assessment Report.
  10. Kim, Y., Hencher, S.R., Yoon, Y., Cho, S. (2002), "Determination of the construction method for Young Dong Tunnel by risk assessment", Tunneling Technology, Vol. 4, No. 1, pp. 13-25.