Augsburg Transportation Hub, Germany – New construction of the West Tunnel
The Augsburg City project is the largest urban development to have been undertaken within the last decades in Augsburg, Germany. The redevelopment of local public transport under the name of "Mobilitaetsdrehscheibe Augsburg – MDA" (Augsburg transportation hub) is part of this project.
The goals are a better connection between the city's different means of transport and the expansion of the tram network. For this purpose, the central interchange square for busses and trams is being converted, the tracks are being relocated and two new tram lines are being introduced.
The central section of the MDA is the multilevel underground structure for the entire main station that also includes the construction of a 405 m long, double track tram tunnel and a new station. In the up to 14 m deep and approximately 70 m long excavation for the West Tunnel, the contractor Stump Spezialtiefbau GmbH installed soldier piles for the soldier pile structure that was tied back in several locations. To ensure the continuation of train traffic during construction work, transverse steel girders or longitudinal structures were installed as sheeting wall systems in some areas.
362 temporary strand anchors were used
Temporary strand anchors were especially used near the tram terminal loop. Here, 182 4-strand anchors with a total length of 2,964 m, 140 5-strand anchors with a total length of 2,292 m and 40 6-strand anchors (total length of 724 m) were used.
The tiebacks were installed using superposition drilling. In some areas, there were up to three levels of anchors crossing each other, which required drilling tolerances of a maximum of 1°.
The tunnel structure had been concreted as a trough structure in sections with floor slabs, walls and corners until the end of 2016. Afterwards, the excavation was backfilled, and the tracks on the surface resumed operation.