The increase of bored tunnels 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. 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 tutorial the model is used to evaluate different design aspects of the tunnel lining. These model is subjected to rock load, seismic load for analysis. The Rock Mass Rating (RMR) from Rock Quality Designation (RQD) is the basis of the design input. The purpose of which is to show that tunnel lining behaviour can be understood, with relatively simple model. The advantage of simple model 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, may also be considered, as applicable.
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The increase of bored tunnels 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. 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 tutorial the model is used to evaluate different design aspects of the tunnel lining. These model is subjected to rock load, seismic load for analysis. The Rock Mass Rating (RMR) from Rock Quality Designation (RQD) is the basis of the design input. The purpose of which is to show that tunnel lining behaviour can be understood, with relatively simple model. The advantage of simple model 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, may also be considered, as applicable.
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