Summary
As a part of a research program on the rock engineering aspects of hard rock subsea tunnelling, analyses of potential cave-in from fault zones have been carried out at the Norwegian Institute of Technology. This is a topic of great importance for the planning of future subsea tunnels, and particularly for the selection of the minimum rock cover of such projects. The paper is divided into three main parts: a) review of cases of instability in Norwegian subsea tunnels, b) evaluation of theoretical maximum sliding, and c) discussion of cases of cave-in in tunnels under land. In theory, a cave-in during subsea tunnelling may propagate far higher than the normal minimum rock cover. Taking into consideration the comprehensive geo-investigations that are always carried out for subsea tunnel projects today, it would, however, be unrealistic to base the dimensioning of rock cover for future projects on worst-case scenarios. Consequently, the main result of this study is to emphasize the importance of comprehensive geo-investigations, detailed tunnel mapping, a high degree of readiness during tunnelling and a thorough quality control.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Brekke, T., Selmer-Olsen, R. (1965): Stability problems in underground constructions caused by montomorillonite-carrying joints and faults. Eng. Geol. 1 (1), 3–19.
Dahlø, T. S., Nilsen, B. (1990): Stability and rock cover for subsea tunnels. In: Krokeborg, J. (ed.), Strait crossings, Proc., 2nd Int. Symposium on Strait Crossings, Trondheim; Balkema, Rotterdam, 193–201.
Grønhaug, A. (1972): Investigations of cave-in at Rørvikskaret road tunnel. (In Norwegian). Proc., Annual Swedish National Conference on Rock Mechanics, Stockholm; IVA, 227–237.
Lu, M., Nilsen, B. (1990): Analytical study of the minimum rock cover for subsea tunnels. In: Krokeborg, J. (ed.): Strait crossings, Proc., 2nd Int. Symposium on Strait Crossings, Trondheim; Balkema, Rotterdam, 201–208.
Miyaguchi, K. (1986): Maintenance of the Kanmon railroad tunnels. Tunnelling Underground Space Technol 1 (3/4), 307–314.
Nilsen, B. (1990): The optimum rock cover for subsea tunnels. In: Hustrulid, W. A., Johnson, G. A. (eds.): Rock mechanical contributions and challenges, Proc., 31st U.S. Symposium on Rock Mechanics, Golden; Balkema, Rotterdam, 1005–1012.
Nilsen, B., Maage, M., Dahlø, T. S., Hammer, T. A., Smeplass, S. (1988): Undersea tunnels in Norway: a state-of-the-art review. Tunnels Tunnelling 20 (9), 18–22.
Olsen, A., Blindheim, O. T. (1989): Prevention is better than cure. Tunnels Tunnelling 21 (3), 41–44.
Thidemann, A. (1981): Long term stability in water tunnels (In Norwegian) Dr.ing. thesis, Norwegian Institute of Technology, Trondheim.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nilsen, B. Analysis of potential cave-in from fault zones in hard rock subsea tunnels. Rock Mech Rock Engng 27, 63–75 (1994). https://doi.org/10.1007/BF01020205
Issue Date:
DOI: https://doi.org/10.1007/BF01020205