AXISYMMETRIC ANALYSIS OF GROUND REINFORCING TUNNELLING DESIGN

The convergence confinement method has been widely applied to tunnel support design due to the simplicity of the used numerical approach. Many different analytical expressions have been proposed in technical literature. A solution able to take into account the existence of an area with different properties around the tunnel has been proposed in this paper. The ground behaviour considered for the analytical formulation includes a strain softening law both for the reinforced or disturbed area and for the natural ground. The proposed model has been tested and found consistent with a well-known numerical model. Some examples, where the importance of the various parameters involved is shown, are also discussed.