ABSTRACT
The 1622 m long Tunnel de Champel in Geneva, Switzerland forms part of the rail-link CEVA (Cornavin, Eaux-Vives, Annemasse) to France. The plateau of Champel is formed by glacial deposits of interglacial and postglacial deposits from the Arve and Rhone glaciers and rivers, with 10 to 30 m overburden. The sections with tunnelling were relatively short therefore conventional tunnelling was selected with a pipe-roof umbrella and face stabilization with fibre-glass anchors.The behaviour of the advancing tunnel was modelled with a three-dimensional Finite Element model. The excavation was monitored in the tunnel, geodetically, inverse extensometers at the face and horizontal inclinometers in the roof umbrella, and at the ground surface with settlement and geodetic monitoring. The buildings on the surface were statically analysed and their risk to settlement evaluated. The comprehensive site investigation, detailed analyses and meticulous construction procedures proved decisive for a safe construction.
