The Albaufstieg: DSI supplies Tunneling Products for High Speed Rail Line
The Stuttgart-Ulm railway project includes several major projects that will shift traffic from the roads to the rails. The existing, winding rail line south-east of Stuttgart over the Swabian Alb only allows peak speeds of 70km/h. In the future, ICE and TGV traffic will be transferred to a new line that will allow maximum speeds of up to 250km/h on a 30.4km long tunnel section through the low mountain range. DSI Austria participated in the construction of two tunnel structures in the 15km long Albaufstieg section – the 8.8km long Bossler Tunnel and the 4.8km long Steinbuehl Tunnel. At an inclination of 17-25 ‰, this section reaches a height of 750m above sea level at its highest point. The Bossler Tunnel overcomes a total change in elevation of approx. 213m and has a cover of up to 280m. After its completion, the double tube tunnel with two rails will be one of Germany’s longest railway tunnels. The structure is being advanced from the western portal on a 2,830m long section using a Tunnel Boring Machine (TBM) in the direction of the eastern portal. The 20,000 segmental liners that are needed for the tunnel are produced in a field factory. The ensuing tunneling work is being undertaken using blasting advance and shotcrete. The double tube, single track Steinbuehl Tunnel is advanced using conventional blasting. The Jura geology at the Albaufstieg is a major challenge for tunneling. The section is located in brown Jura with low rock stability and in Oxfordian and compact limestone formations, the latter of which tends to have karst formations and a high water potential. Tunneling is first carried out at the crown, which is stabilized using rock anchors, 3 bar Lattice Girders and shotcrete. After an advance section of approx. 500m, the bench and invert are blasted and dug off. In the rock areas that are sensitive to load shifting, the tunnel is advanced using an 11m diameter full-circle tunnel heading with fast ring closure. DSI Austria supplied several high quality products and systems for stabilizing tunnel advancement. DYWI® Drill Hollow Bar Anchors and Self-Drilling Spiles, SN Anchors, DYWIDAG GRP Anchors, Lattice Girders and OMEGA-BOLT® Rock Bolts were some of the products used for rock support.