DYWIDAG Geotechnic Systems Secure new Rail Line
The expansion of the rail network between Stuttgart and Ulm is an important part of what is known as the Magistrale for Europe: The railway corridor that connects Paris and Budapest. This project also includes the expansion of the new rail line between the towns of Wendlingen and Ulm as well as the connection with and the lowering of Stuttgart’s main station.
In the planned 1.2km long PFA 2.5a1 section, the main station in Ulm is being rebuilt and connected to the new rail line. In the run-up to the construction work at the station, the access roads to the jobsite as well as to the future emergency rescue area are under construction. Simultaneously, the existing railway overpass is being dismantled. The new overpass will be built in the excavation pit and slid in place afterwards.
A Berlin-type support system filled in with wood and shotcrete was chosen for the up to 8.80m deep excavation pit. To stabilize the support walls, one layer of bracing and 4 layers of temporary, Type 4-0,60" and 5-0,60" DYWIDAG Strand Anchors were installed. The total length of the 86 strand anchors used was 2,050m with a maximum anchor length of 31.5m.
This sub-project includes the construction of the Albabstieg Tunnel’s portal wall as well as the portal structures including the subsequent troughs 1 to 3. The portal wall was constructed up to a depth of approx. 27.0m. For this purpose, the existing gallery was stabilized using permanent DYWIDAG Strand Anchors, and the adjacent embankment was stabilized using shotcrete and GEWI® Rock Bolts.
The excavation of the tunnel portal underneath was built using an intermittent, tied-back bored pile wall.
The excavation walls, which were partly tied back in 8 sections, were constructed using 194 temporary and 146 permanent Type 4-0.60", 5-0.60" and 7-0.60" DYWIDAG Strand Anchors. In total,3700m of anchors with maximum lengths of 37.5m were installed. In addition, 102 25mm Ø GEWI® Rock Bolts with a total length of 538m were used. The adjacent excavation pits for the troughs TN1-3 were built using sheet pile walls. For this purpose, the lime stone in the construction soil was drilled out. The tie-backs, consisting of 80 temporary and 60 permanent Type 4-0.60" and 5-0.60" DYWIDAG Strand Anchors with a total length of 2,100m, were installed in 2 layers.