Spectrum of tunnel rehabilitation extended

06.12.2019

Marti Germany is renovating and extending an electrified railway tunnel under traffic. The so-called tunnel widening system, developed by Marti Technik, is the decisive factor here. The Petersberg Tunnel Expansion project sets new standards and demonstrates the innovative strength of Marti engineers.

The number of passengers and tonnages transported by rail is rising steadily. The load on the rail system is constantly increasing. At the same time, many sections are getting on in years and refurbishments are becoming necessary. This is particularly difficult in tunnels with overhead lines. Long closures are expensive and inefficient. The question is: How can a tunnel with overhead contact lines be rehabilitated under traffic and closures be reduced to a minimum?

The answer was provided by ARGE Tunnel Petersberg, a joint venture of
Marti Tunnel, Marti Luzern and Marti Deutschland.

Renovating and enlarging a tunnel - that's what engineers plan again and again. "But with the Petersberg Tunnel on the Moselle route from Koblenz to Trier, they are setting standards," writes Prof. Dr.-Ing. Dietmar Mähner of the Institute for Underground Construction at Münster University of Applied Sciences.

Safety as a driver of innovation

Already in the bidding phase, Marti engineers developed various concepts to combine technology, innovation and safety. For the Petersberg Tunnel, they developed a tunnel widening system that offers protection against the dangers of excavation work. Additionally, a continuous protective enclosure with integrated overhead contact line was developed. This, too, is a novelty.

The decisive element of the project is the tunnel extension portal consisting of three carriages developed by Marti Technik. It combines all the equipment needed to widen and secure the vault. Drilling equipment and spraying robots are mounted on the sides, and a hammer drill is installed at the top of the ridge to excavate the vault.

Arch protection brings efficiency

A special feature is the first carriage. A hydraulic arch protection that supports the existing arch during blasting and excavation. This eliminates the need of securing with additional anchors. The entire extension portal withstands the pressure of the blasting and the rock pressure.

After completion of the project, Prof. Mährer summarised: "This project has considerably expanded the spectrum of tunnel renewal"