Ulm, one of Germany’s most ancient cities, lies at the point where rivers Blau and Iller join the Danube. Across from the old town, on the far side of the river, lies Ulm’s twin city of Neu-Ulm in the state of Bavaria.
Every two hours the ground shudders as another explosion resonates in one of the tunnels being excavated through the Alb Plateau to take Germany’s high-speed ICE – Inter City Express – right into the center of Ulm. Behind the project is Deutsche Bahn, Germany’s national railway.
Work on the twin-bore Albabstieg tunnels began last year and a tight schedule has been set to carve through 4km of limestone rock and emerge in front of Ulm main station – in the shadow of Ulm’s great 14th Century gothic cathedral – by December 2017. A fleet of Volvo Construction Equipment (Volvo CE) machines are helping to achieve this enormous task.
The tunnel is the final link between Stuttgart and Ulm central station for the ICE, the fastest of the Deutsche Bahn trains. It connects all the major German cities, such as Frankfurt, Hamburg, Stuttgart, Munich, Cologne and Berlin. The next stop will be Ulm. Though the ICE can travel at 330km/h, there is a speed limit of 250km/h on the Ulm line.
The construction consortium, ARGE Tunnel Albabstieg, is responsible for building the tunnel. The project involves excavating two single-track rail tunnels from the town of Dornstadt to Ulm. Each bore is more than nine meters in diameter and 5.9km in length, with a 400-500mm thick, concrete inner shell.
In November 2013, Volvo CE dealership Robert Aebi GmbH was awarded the contract to supply nine Volvo L150 wheel loaders – four G-Series and five H-Series and a further 10 Volvo A30 articulated haulers, eight F-Series and two G-Series.
“We needed machines that could provide the reliability, service and back-up required for such an intensive tunneling schedule,” says ARGE project manager, Mathias Abele.
“My experience of working with Volvo on previous projects was positive enough to give me the confidence that its machines could provide the service and reliability required for the project,” says Eric Lüpfert, mechanical engineer at ARGE. “The wheel loaders and articulated haulers have been specially configured for tunnel work, including custom tires, air filters, automatic engine cut-out systems, automatic fire extinguishers, optical and acoustic reversing warning devices, LED lighting, protective headlamp guards and reinforced heavy-duty cabin roofs.”
The construction company had also decided it wanted to purchase outright, rather than rent – it was important for ARGE to deal with one reliable supplier, rather than many.
“As far as ARGE and Deutsche Bahn are concerned, every link in the extraction chain has to be solid and unbreakable,” explains Manfred Prinz, sales manager at the Robert Aebi dealership. “The contribution from our machines will be to keep this extraction carousel going day in, day out, for two-and-a-half years.”
The twin tunnels to Ulm are each being bored at a rate of 15 meters a day. This schedule will run 24-hours, seven days a week until December 2017. Critical to the plan are the wheel loaders and articulated haulers the excavated limestone rubble, as the high-intensity mining operation proceeds.
Each explosion releases many tonnes of blasted limestone, which is then moved by the Volvo wheel loaders on to Volvo articulated haulers for transporting to designated recycling sites. The blasted material is sorted and reprocessed on-site, then sold on for use in cement production.
For the fleet of Volvo articulated haulers, this work schedule represents an estimated 370 round trips every 24 hours. Over the life of the project, the Volvo machines will shift an estimated three million tonnes of excavated rock.
As tunneling progresses, the demands will increase. The final stages of the project will see the Volvo haulers making an 8km round trip to the ‘business end’ of the tunnel, returning up a gentle incline with their 30-tonne loads. This will certainly test the performance of the Volvo carousel, although both ARGE and Volvo CE are confident of the machines living up to expectations.
Manfred Prinz emphasizes the lengths his company has gone to in meeting the need for machine reliability and availability. In addition to the fleet of machines purchased for the tunnel project, the dealer has placed an L150 wheel loader and an A30 articulated haulers on-site, available as standby machines for the contractor.
While day-to-day maintenance is undertaken on-site by ARGE, specialists at the Robert Aebi dealership are just 20 km away, on call for technical support and ready to intervene whenever necessary.
“Nothing is left to chance,” Prinz stresses. “The 24/7 tunneling schedule cannot be allowed to stop. In addition to supplying them with high-performance machines, we are capable of providing the level of back-up and support they require for this time-critical project.”