Robots drill 9,000 holes during tunnel upgrade in Germany

The Fischer BauBots were put to work on a project to carry out structural and operational upgrades to the Engelberg Tunnel in Leonberg, in the state of Baden-Württemberg.

The tunnel, part of the A81 federal highway, runs under the Engelberg mountain and is one of the busiest tunnels in southern Germany, with 120,000 vehicles passing through it each day.

The tunnel, built between 1995 and 1999, has suffered damage to sections in both the east- and westbound tunnel tubes.

Geological challenges include anhydrite rock, which swells when it comes into contact with moisture, deforming the tunnel walls and endangering the structure.

Work involves reinforcing the damaged tunnel sections, including the installation of a reinforced concrete facing shell with steel girders to brace the vaults as well as the installation of a suspended ceiling. The road deck is also being reinforced.

All lanes remain open during the work, making for a confined space, meaning that a sophisticated traffic management plan is required.

The BauBots have been used to drill 9,000 holes with a diameter of 20mm and a depth of 240mm for the rapid preparation of anchor points.

Fischer said the robots also feature an integrated dust extraction system to ensure a clean and healthy working environment. Drills and consumables were included in the service package. To minimise downtime, additional robots, end effectors, and operators were also available as replacements.

Each borehole was automatically documented with relevant process parameters such as borehole depth, reinforcement encounters, and other important data, eliminating the need for manual logs.

“The use of our three fischer BauBots significantly increased efficiency and improving quality during the renovation of the Engelberg Tunnel,” said Emil Kral, managing director of BauBot Services. “This project highlights the enormous potential of modern automation solutions in infrastructure construction.”

The Engelberg tunnel upgrade project is due for completion in 2026.