Herrenknecht’s custom designed 13.91 m diameter tunnel boring machine (TBM) completed 3.2 km of tunnelling for the Belchen rehabilitation project last month, 3 months ahead of schedule.
The single shield TBM completed the excavation through the Belchen mountain range – a complex geology of gypsum, clay, lime, dolomites and marl – within 16 months.
When the TBM was launched from Hägendorf on 9 February 2016, Swiss Federal Roads Office (FEDRO) Director Jürg Röthlisberger said that the concept of the project was “construction without queues”.
The machine, 75 m in length and weighing 2,000 t, completed up to 90 m of tunnelling per week under the direction of Marti Tunnelbau AG, which FEDRO commissioned for the project.
The Belchen Tunnel comprises a twin tube road tunnel that stretches between Basel and Lucerne, through the Jura Mountains, and is used by a significant amount of the north-south road traffic and domestic Swiss traffic.
With more than 55,000 vehicles passing through the tunnels each day, the importance of ensuring operational safety is urgent.
Marti Tunnelbau AG completed the rehabilitation tunnel 40-116 m to the west of the existing tunnel system, despite the challenging conditions.
“Thanks to the comprehensive knowledge of the ground conditions from the two existing tunnel tubes, coupled with our experience and Herrenknecht’s know-how, the machine was optimally designed for the demanding requirements of the alignment of the Belchen rehabilitation tunnel,” said Marti Tunnelbau AG Site Manager Sergio Massignani.
Final works inside the rehabilitation tunnel are expected to be complete and ready for commissioning in 2021, when the existing twin tube tunnels will be renovated.