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Structural Design of Linings for Bored Tunnels in Soft Ground

Author: Bakker, K.J.
Faculty:Civil Engineering and Geosciences
Type:Article/Letter to the Editor
Date:2003-06-01
Publisher: Delft University of Technology
Source:Heron, Vol. 48 (2003) No. 1, pp. 33-63.
ISSN: 15744078
Rights: (c) K.J. Bakker

The increase of bored tunnels in the Netherlands has raised the question how to design the tunnel structure in an efficient way. As a large part of the cost of a bore tunnel is related to the cost of the lining, it is important to design the lining in a cost-effective way. In the Netherlands it is customary to base the structural design of tunnel linings, on the use of models, validated models. Due to the increased flexibility in modelling quite often in engineering practice these models are numerical. Numerical models however are sometimes difficult to interpret, this contrary to the clarity of most empirical and analytical models. In this paper a number of, these simple models are used to evaluate different design aspects of the tunnel lining. These models are discussed in a comparison with measurements and results of more elaborate numerical analysis. The purpose of which is to show that tunnel lining behaviour can be understood, with relatively simple models. The advantage of simple models is that these can be used for a 1st order covering of the dominant mechanisms and for preliminary design. Empirical relations and analytical solutions generally give a good insight in the relevant issues. However to take into account the complexity of geometry, geology and construction method, in practice for a final design numerical models are necessary. Finally, a number of special issues, such as 3D effects, creep and longitudinal effects in the tunnel tube, and in addition to that, the effects of fire as well as some aspects of durability, are discussed.

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