Comparisons of Eurocodes design approaches for numerical analysis of shallow tunnels

Although Eurocode 7 is not meant to be applied to the design of tunnels, the lack of standard codes explicitly focusing on tunneling leads to the situation that it is increasingly used in practice, at least for shallow tunnels in soil. However, there is no general agreement on which of the approaches defined in EC7 is the most suitable for the design of shallow tunnels, in particular when it comes to applying them in combination with numerical analyses. In this paper, the results of numerical calculations aimed at assessing ultimate limit state conditions of a shallow tunnel in soil are presented. The focus of the present work is firstly on the verification of the applicability of the Eurocodes in combination with numerical analyses and the comparison of different design approaches. Secondly, the consequences of the choice of a nonlinear material model for the shotcrete primary lining are discussed.