The tunnel boring machine in Airolo is ready for use
The tunnel boring machine in Airolo is ready for use

The tunnel boring machine in Airolo is ready for use

The official green light for excavation of the Gotthard South access tunnel (lot 343) took place with a special ceremony in Airolo on June 9, 2022. The cutting wheel of the pink tunnel boring machine was still symbol­ically turning in front of the portal on this festive occasion. It will soon carry out its work inside the launch tube, drilling some 5 km to the north.

In January 2022, the tunnel boring machine (TBM) was formally accepted on-site during factory acceptance and sub­sequently dis­assembled into individual parts suitable for transport. These were then trans­ported to Airolo using heavy, special, subsequent transports that were time-consuming both in terms of planning and logistics. Some of the individual parts were so heavy and bulky that on­coming traffic had to be stopped on some bridges and in the Gotthard tunnel during transport.

The exper­ienced assembly crew took over the dis­assembled TBM at the installation site in Airolo. It took weeks to re­assemble and repair, and is now ready for operation.

“The tunnel boring ma­chine, with its unusual color, already drew a lot of atten­tion at the manu­facturing plant in Schwanau, Germany. When­ever an em­ployee or visitor walked past the machine, they would in­variably stop to take a picture.”
Bruno Ollio,
Machine operator, Marti Tunnel AG

The TBM has now moved forward through the 80 m long launch tube to the rock and is being equipped with the remaining trailing elements. This launch tube was driven in granular soil for geological and constructional reasons. The geology found there has proven extremely difficult. This is why seven of the eight originally planned pipe arch stages had to be secured using the more complex jet grouting process.

Starting in the summer, the TBM will head north to a fault zone, the “Guspis zone,” about 5 km from the portal in Airolo. This fault zone will later be crossed and secured through the main lot 341. This en­sures that the large TBM (12.6 m in diameter) required for the road tunnel can pass through this area without any compli­cations. Once the road tunnel is completed, this access tunnel will be used as a venti­lation and drainage tunnel during operation.

Hard Facts

  • Lot 343 Access Tunnel Gotthard South is a subproject of the second tube of the Gotthard Road Tunnel (2TG).
  • The diameter of the TBM is 7.4 m
  • The machine has a total length of 175 m and a total weight of around 1,110 t

the stakeholders include