Three-dimensional finite element analysis of lined tunnels

This paper describes finite element procedures that have been developed to model the ground movements that occur when a shallow tunnel is installed in a clay soil. This study is part of a wider project concerned with the deve lopment of new methods to predict the likely extent of damage to surface st ructures caused by nearby shallow tunnelling. This particular paper, howeve r, is concerned only with the numerical model of tunnel installation. The s tructural liner is an important component of this tunnel installation model ; two different ways of modelling the liner (based on continuum elements an d shell elements) are discussed in the payer. A test problem consisting of the installation of a lined tunnel in an elastic continuum is used to inves tigate the merits of these different approaches. When continuum elements ar e used to model the liner, the numerical results agree well with an analyti cal solution to the problem. When shell elements are used to model the line r, however, the results were found to be significantly influenced by the pa rticular formulation adopted for the shell elements. Example analyses, invo lving incremental tunnel construction in a clay soil where the soil is mode lled using a kinematic hardening plasticity model, are described. These ana lyses confirm that a thin layer of continuum elements may be used, satisfac torily, to model tunnel linings in a soil-structure interaction analysis of this sort. Copyright (C) 2001 John Wiley & Sons, Ltd.