Early brekthrough at Tunnel de Saverne
7 September 2012The first tube has broken through on Tunnel de Saverne. The machine boring the high speed rail project in the Vosges Mountains in eastern France reached the western side two months ahead of schedule. Contractors Spie Batignolles TPCI and Dodin Campenon Bernard worked for client Resau Ferre de France.
The Herrenknecht machine that excavated the approximately 4km-long first tube began work in November 2011 and took seven months. It saw a daily best advance rate of 46m and a week best of 250m.
The 10.01m diameter machine was built as an open convertible EPB shield capable of excavating two soil types. The initial 200m of the drive were in unconsolidated rock comprising sandstone and shell limestone. In closed mode it could drive through the prevailing geology of hard red sandstone then continue in open mode for the rest of the bore.
A Herrenknecht spokesman said, "This is the first time a Herrenknecht TBM with a convertible EPB shield has been used that can also handle the open hard rock mode with belt conveyor discharge."
Herrenknecht project manager Stephan Hanusek said, "The conversion went without a hitch, so the machine was ready again in a few days."
The second tube will begin excavation in October.
