This study focused on the development of 2-dimensional finite element analysis technique for 3-dimensional ground behaviour due to tunnelling. An extensive literature and published papers on the 3-dimensional effects under tunnelling are reviewed, and 3-dimensional finite element analyses have been carried out for specific tunnels with different ground conditions and various excavation techniques which have been frequently encountered in Korea.
The Nomalized Displacement Ratio(NDR) curve obtained from comprehensive 3-dimensional finite element analyses was found to be unique irrespective of the shape of tunnel and the ground conditions. Therefore the 3-dimensional ground behaviour can be successfully represented by much simpler 2-dimensional finite element analysis with this Normalized Displacement Ratio(NDR) curve.
Furthermore, this Nomalized Displacement Ratio(NDR) curve may be useful for the prediction of total deformation and the interpretation of the rate of settlement corresponding to the location of tunnel face during tunnelling. Thus it can be very useful in safe, realistic, and economical management of tunnel construction when compared in-situ monitored results.
