Geotechnical Challenges and Technical Solutions for Settlements Reduction for the New Access Gallery to the Ceneri base Tunnel (Switzerland)

This paper deals with the main results of an extensive monitoring campaign carried out to quantify the vertical displacement due to the installation of some pre-loads to be realized before the construction of an artificial tunnel.As part of the "Sigirino access tunnel" project, this concrete structure will be realized on highly deformable, saturated silty so that some relevant settlements are expected, therefore they must be minimized to satisfy Serviceability Limit State requirements.Monitoring results are compared with outcomes given by bidimensional finite element analysis, to provide the basis for an appropriate design of the tunnel and to predict the stress-strain response of the structure itself during its work life.