Safer tunneling through the use of the AT – Pipe Umbrella System
Safer tunneling through the use of the
AT – Pipe Umbrella System
The new Stuttgart-Ulm line, with ist centrepiece the new Stuttgart railway junction, widely known as Stuttgart 21, is currently Germany’s largest infrastructure construction site. The sub projects, lot 1A Filder Tunnel and lot 1B Oberand Unterturkenheim access tunnel comprise the construction of twin-tube railway tunnels by the Austrian Tunnel Consortium Stuttgart 21 (ATCOST21). The Filder Tunnel has a length of 9.4 km and the Oberturkheim and Unterturkheim Tunnels has a length of 6 km.
The drives of about 30 km of tunnels are being carried out starting with three faces by tunnel boring machines (TBM) as well as tunneling by conventional excavation and blasting. The majority of the Filder tunnel was produced using a TBM, however the middle sections which were located in difficult ground conditions were excavated conventionally. The tunneling work for the Oberand Unterturkheim Tunnel was carried out from the access on Ulmer Strase via a 37 m deep shaft. In the course of this construction phase, the first crossing of the River Neckar was made by a tunnel that was excavated by mining. The production of the underground buildings in the area of the main stationsouth approach area was also a particular challenge. The tunnel, which lies just under the buildings and has an excavated cross-section of up to 200 m2, had to be constructed in compliance with strict settlement criteria.
Due to the extraordinary tunnel construction challenges, the AT – Pipe Umbrella System was used for the excavation of the two conventional tunnel structures. The AT – 168 × 12.5 mm Pipe Umbrella System with a length of 16 m was used; two automatic tube shield systems were used for installation. In addition to the AT – Pipe Umbrellas, the DSI Hollow Bar System (types R32- 320, R32-360 and R38-550) and the AT – Drainage System were used for predrainage. During the interim work at Ulmer Strase, single or double AT – 139 × 8.0 mm Pipe Umbrellas with a length of 15 m were produced with four AT – Pipe Umbrella Automation. Currently, the Oberturkheim countertunneling system is operated under the railway line with a single and double AT – 139 × 8.0 mm Pipe Umbrella System with a length of 18 m.
The fully mechanized installation of the AT – Pipe Umbrella System significantly increases occupational safety. The construction companies benefit from the efficient and self-drilling installation technology and the production of the AT – Pipe Umbrella using standard drilling equipment as well as by the construction site’s own staff. The use of AT – Pipe Umbrella Automation Unit guarantees a smaller saw tooth profile and thus lower excavated volume. The handling of the pipe umbrella tubes with a considerable operating weight is considerably simplified.