DSI supplies Tunneling Systems for the Construction of Goetschka and Freistadt Tunnels
In 2009, construction began on the S10 Muehlviertel Highway in Upper Austria. The new S10 highway connects to the existing Muehlkreis A7 Motorway north of Linz near Unterweitersdorf and extends to the former border crossing near Wullowitz, Czech Republic, over a total length of 38km.
The S10 is considered to be a crucial road connection for the Muehlviertel region. It will considerably enhance traffic safety in this area, create strong economic stimulus for the town of Freistadt and the Muehlviertel region and create a better traffic-related and economy-related network between the region of Freistadt and the greater Linz area. The 22km long southern section of the S10 will be fully developed as a highway and will include four lanes with an additional hard shoulder. More than 40% of the complete route runs through four tunnels and subsurface routes. During the planning phase, when the environmental impact of the project was reviewed, many measures were developed to either avoid or compensate for adverse effects along the track. The Goetschka Tunnel is the largest single building contract in the history of Austria’s ASFINAG highway authority. The double tube tunnel is being built on a length of approx. 4.4km between the communities of Unterweitersdorf and Matzelsdorf north-east of Linz. The eastern tube in the direction of Prague is being built with three lanes due to the ascending slope of up to 3.6%: two regular lanes and one slow lane. The western tube in the direction of Linz will include two lanes. The two tunnel tubes with a total length of 8.8km will be equipped with modern safety features. The axis-center distance of the two tunnel tubes measures between 17 and 45m. Both tubes will be connected via a total of 17 crosscuts, four of which will also be accessible by emergency vehicles. Following are some key technical details for the Goetschka Tunnel:
- Eastern tube: 3 lanes with a width of 11m; length: 4,432.5m; approx. 115 m² of excavation section
- Western tube: 2 lanes with a width of 7.50m; length: 4,454m; approx. 86.5m² of excavation section
The maximum overburden in the tunnel area is 110m. The total excavation material that is expected for both tunnel tubes is approx. 1.1 million m³, 300,000m³ of which will be re-used in the tunnel. The Goetschka Tunnel leads through some demanding geological conditions, making excavation for the miners challenging. Excavation is carried out in accordance with the New Austrian Tunneling Method (NATM). DSI supplied Lattice Girders, SN Anchors with ALWAGRIP special rib geometry, steel spiles, tube spiles, DYWI® Drill Hollow Bar Anchors including accessories, OMEGA-BOLT Anchors and permanent DYWIDAG Strand Anchors in lengths of 21 and 26m. The products were used both for stabilizing the precuts and the excavation work for both the Goetschka and Freistadt Tunnels. The installation of 200 permanent 5-0.62" DYWIDAG Strand Anchors in lengths of 21m at the breakdown bays in the 3-lane eastern tube posed a special challenge at Goetschka Tunnel. The DYWIDAG Strand Anchors had to arrive at the tunnel site complete with a special foot plate that prevented the sliding out of the strands and sealed the borehole. The strand anchors for the breakdown bays were installed vertically using coils and a special mounting designed by Porr and then tensioned by DSI experts. The completion of the project with its total length of 38km is scheduled for autumn 2015.