Numerical study of low depth tunnel behaviour

The paper presents the results of a research developed jointly by Italferr S.p.A. and the Dept. of Georesorces and Land of Politecnico di Torino which had the goal to study the behaviour of surface tunnels in different types of ground. A parametrical study using tridimentional numerical modelling has been carried out to determine the face stability conditions for tunnels at low depth. A systematical comparison between 3D and 2D numerical models has been carried out. The results have shown that the displacements of a surface tunnel developes mainly ahead of the tunnel face and from these some suggestions for the improvement of the bidimentional numerical modelling are presented and discussed.