For Euro Alliance Tunnels May 7th can be marked as a day of the next tunnel breakthrough. After six months the first tube of tunnel Metzberg was broken through successfully. The excavation of the tube, which is 530 m long, with cross section 90 m2 was executed using the NATM with subdivision of the cross-section into top heading and bench. As every tunnel project is unique, so is this - the unstable geology with many weak zones caused several difficulties. One huge hollow space broke out and the cavity had to be closed using injections and grouting mortar. Also the strengthening and reinforcement had to be customized and enhanced continuously to ensure all relevant requirements on safety and stability.
Tunnel Metzberg is one of six railway tunnels with total length over 6.000 m, belonging to the project Bypass of Schwarzkopftunnel in the German mountain Spessart in North Bavaria. After all finishing work following the breakthrough the second parallel tube is going to be excavated. Simultaneously both tubes of tunnel Falkenberg are being excavated by our engineers and tunnel workers.
