An important part of the S1 Vienna outer ring expressway is the tunnel under the Danube and Lobau with a length of 8.3 m. The ground to be tunnelled through is marked by Quaternary gravels and also by silt/clay with sand layers with low silt content. About 6 km are thus to be bored by two closed tunnel boring machines. A detailed material recycling plan for the entire S1 was produced for the processing of the excavation spoil. The excavated material was categorised according to its quality into various categories for appropriate recycling. The greatest possible free play for economic solutions has to be balanced with high requirements for the protection of people and the environment. Project descriptionThe S1 Vienna outer ring expressway forms a part of the regional ring of altogether six motorways and expressways with a length of about 200 km, one of the most important road links in Vienna and Lower Austria. 150 km of this has already been built, and the rest is currently in the design stage or under construction. The project S1 Vienna outer ring expressway extends 19 km in the section between Schwechat and Suessenbrunn and represents together with the 8.3 km long tunnel Danube-Lobau an essential part of the regional ring and closes the gap between sections of the S1, which already exist or are under construction.The route of the S1 starts at the A4 Schwechat intersection and runs through tunnel under the Albern harbour, the Danube, the new Danube, the Lobau oil harbour and the Donau-Auen (Danube wetlands) national park northwards. The tunnel is being constructed as cut-andcover in the area south of the Danube, and by the shield method under the Albern harbour, the Danube and the national park. North of the national park, the route goes into another cut-and-cover tunnel and runs as a backfilled box to the north portal (Figure 1).Near the Gross-Enzersdorf junction, the route runs into the open air. The S1 and the S2 Suessenbrunn bypass join up at the Suessenbrunn intersection. The design of the S1 in the section from Schwechat to Suessenbrunn has been handed in for approval and the environmental impact assessment process is currently underway.Ein wesentlicher Bestandteil der S1 Wiener Außenring Schnellstraße ist der Tunnel unter Donau und Lobau mit 8,3 km Länge. Der zu durchfahrende Untergrund ist gekennzeichnet durch quartäre Kiese einerseits und Schluff/Ton mit schluffarmen Sandschichten andererseits. Rund 6 km sollen daher in geschlossener Bauweise mit zwei Tunnelbohrmaschinen hergestellt werden. Zur Abwicklung der anfallenden Ausbruchmassen wurde ein detailliertes Massenverwertungskonzept für die gesamte S1 erstellt. Die anfallenden Massen wurden dazu nach ihrer Qualität in mehrere Kategorien eingeteilt, die einer entsprechenden Verwertung zugeführt werden. Größtmögliche Spielräume für wirtschaftliche Lösungen sind dabei mit den hohen Anforderungen an den Schutz von Mensch und Umwelt in Einklang zu bringen. ProjektvorstellungDie S1 Wiener Außenring Schnellstraße bildet als Teil des Regionenrings mit insgesamt...

The history of autobahn tunnel construction in Austria is about 45 years young, and currently 140 tunnels with a total length of 300 km provide short, safe and environmentally friendly routes for traffic all year round. A further 100 km of tunnel are being designed or are under construction. The present article gives a review of milestones in the history of autobahn tunnel construction and analyses the special features of road tunnels with regard to the method of tunnelling. More detailed descriptions are given of the TBM project A14, 2nd bore of the Pfänder Tunnel and the S1 Danube‐Lobau crossing project currently being designed, including the considerations leading to the selection of tunnelling method in each case. Die Geschichte des Autobahntunnelbaus in Österreich ist rund 45 Jahre jung. 140 Tunnel mit einer Gesamtlänge von 300 km sorgen ganzjährig für kurze, sichere und umweltfreundliche Transportwege. Weitere 100 km Tunnel sind derzeit in Planung bzw. Bau. Der vorliegende Beitrag gibt einen geschichtlichen Rückblick auf Meilensteine im Autobahntunnelbau und analysiert die Besonderheiten von Straßentunneln im Hinblick auf die Vortriebsmethoden. Auf das bereits umgesetzte TVM‐Projekt A14, 2. Röhre Pfändertunnel und das Planungsprojekt S1 Donau‐Lobau‐Querung mit den entsprechenden Baumethodenüberlegungen wird näher eingegangen.

The S1 Donau‐Lobau tunnel closes the gap in the road network around Vienna. Its two tunnel tubes run under the Danube and the Donau‐Auen National Park, with the provision that no work is allowed to take place on the surface of the site. The (hydro‐)geological subsurface conditions in the project area can be described as ”difficult“. The tunnel project must also meet all safety‐related requirements that arise during construction and operation, while at the same time minimizing the environmental impact.This article describes the essential special civil engineering and tunnelling measures in connection with the local subsoil conditions. It outlines the geotechnical exploration goals required for the structural tendering and detailed planning as well as for limiting the subsoil risk. Just obtaining the necessary permits for the exploration work required extensive preparatory work. As a result, both the exploration programme and the tunnel itself have been further adapted. The approved explorations were completed in the shortest possible time in compliance with extensive environmental requirements during a single winter season.