- Volume 27 Issue 2
DOI QR Code
Stability Estimation of the Pillar between Twin Tunnels Considering Various Site Conditions
다양한 현장조건을 고려한 병설터널 필라의 안정성평가
- Received : 2017.04.11
- Accepted : 2017.04.21
- Published : 2017.04.30
A lot of twin tunnels were modelled with different pillar widths, rock mass classes and stress ratios in order to consider various site conditions, and the stabilities of the pillars were estimated by numerical analyses and scaled model tests. The strength-stress ratios of the pillar were obtained from three different methods which were using the stresses appeared at the middle point, the whole average and the left/right edges of the pillar. The strength-stress ratio of the pillar edges showed relatively conservative values among them, and it was also practically consistent with the tunnel excavating steps comprising the construction sequence analyses which included the partial excavation and the support system. Scaled model tests were also performed to investigate the tunnel stability, where it was found that cracks were progressively generated from the pillar edges toward the middle point of the pillar. Therefore, in order to both prevent the local damage of pillar and conservatively estimate the tunnel stability, it was thought to be an appropriate method using the strength-stress ratio obtained from the left/right edges of the pillar.
Twin tunnels;Pillar;Stability;Strength-stress ratio;Scaled model test
- Bieniawski, Z.T., 1989, Engineering rock mass classifications, New York, Wiley.
- Byun, Y.S., H.G., Kim, S.S., Lee and B.S., Chun, 2010, A study on pillar behavior of twin parallel tunnels by numerical approach, Journal of the Korean Geoenvironmental Society, 11.8, 49-55.
- Choi, J.J, 2014, Reinforcement method of a pillar using tension bolts in 2-Arch varying section tunnels, Ph.D. thesis of Suwon University, Korea.
- Design guideline for construction works of national highway, 2013, Ministry of Land, Infrastructure and Transport, Korea, 395.
- Hoek, E. and E.T., Brown, 1980, Underground excavation in rock, Institution of mining and metallurgy, London.
- Kim, D.S. and Y.G. Kim, 2007, A study on the stability analysis for asymmetry parallel tunnel with rock pillar, Journal of Korean Tunnelling and Underground Space Association, 9.4, 387-401.
- Kim, J.W., 2012, A study on the stability of asymmetrical twin tunnels in alternating rock layers using scaled model tests, Tunnel and Underground Space, 22.1, 22-31. https://doi.org/10.7474/TUS.2012.22.1.022
- Kim, J.W., 2015, Influence of pillar width on the stability of twin tunnels using scaled model tests, Tunnel and Underground Space, 25.5, 423-434. https://doi.org/10.7474/TUS.2015.25.5.423
- Kim J.W. and S. Heo, 2016, Stability investigation of a foundation located above limestone cavities using scaled model tests, Tunnel and Underground Space, 26.6, 493-507. https://doi.org/10.7474/TUS.2016.26.6.493
- Kim, W.B., H.S., Yang and T.W. Ha, 2012, An assessment of rock pillar behavior in very near parallel tunnel, Tunnel and Underground Space, 22.1, 60-68. https://doi.org/10.7474/TUS.2012.22.1.060
- Matsuda, T., E. Toyosato, M. Igarashi, Y. Nashimoto and T. Sugiyama, 1997, A study on design methods for twin tunnels constructed by the single drift and central pier method, Proceeding of Studies on Tunnel Engineering, Vol. 7.
- Peck, R.B., 1969, Deep excavations and tunnelling in soft grouting, Proc. 7th ICSMFE, Mexico, State-of-the-art Report, 225-290.
- Tunnel design criteria, 2007, Ministry of Construction and Transportation, Korea, 17.