Schottenberg Tunnel

The B 101 federal highway from Berlin to Aue serves as a motorway access to the A 14 and A4 in the Meißen area. Work on construction section II for the Meißen Bypass, with the Schottenberg Tunnel at its core, began on March 31st, 2003 with the production of the "Kynastspange”. Operations on the Schottenberg Tunnel itself commenced on April 13th, 2004. The Schottenberg Tunnel comprises the 718.8 m long main bore with 3 lanes and a clear section of 13.5 x 4.5 m. ln keeping with the geological conditions the tunnel is being produced in one cross-section in the form of an assembled basket arch with open and closed floor The carriageway is divided into 2 lanes uphill (3.50/3.25 m wide) and one lane downhill (3.75 m) with 2 emergency pathways at the other edges (each 100 m). The gradient drops towards the Elbe with a max. incline of 5 %. Cross-passages are set up between the main tunnel and the rescue tunnel at roughly 150 m gaps, which serve as escapeways in the event of evacuation. The rescue tunnel is 770 m long, 2.8 m wide and 3.1 m high. It is extended to form a cross-section of approx. 40 m² in sectors housing the 20 m long ventilation stations and the lay-bys. The tunnel penetrates limnic-fluvial soft ground, weathered rock with soft ground character and granite/rhyolith of the Meißner granite massif given an average overburden varying from 24 to 36 m. The mined section of the 2 drives is created using the NATM with drill+blast as well as excavators in certain stretches. The entire cross-section is produced in part-sections (crown, bench and partially a base invert). The crown is driven depending on the weathering classes in lengths of 1.0 to 1.8 m in the main tunnel and 0.8 to 1.5 m in the rescue tunnel. A base invert is only installed in areas with poor geology. The degrees of weathering of the rock increase as the drive progresses from east to west and in turn, the material required to secure the rock. This is, by and large, accomplished using shotcrete, steel or lattice arches, reinforced concrete mats, steel bolts, steel lances or girders. The excavated material is only capable of being reutilised to a minor extent (20,000 m³) owing to the high degree of weathering. The bulk of it has to be disposed of. Over the final 65 m in the western part, an area in which the quaternary prevails, pipe umbrella sections are driven so the excavation can be carried out in the form of a one-sided wall heading using excavators. The tunnel and the rescue tunnel are to be provided with a membrane seal consisting of a 2 mm thick plastic foil as umbrella shield. Any seepage water that is present is disposed of by drainage systems beneath the verges. Together with the tunnel, an operations centre on the Leipziger Straße, a retention basin for toxic substances and rainwater, a drainage trench as well as an extinguishing water container are to be set up.

Country: Germany
Region: Saxony
Tunnel utilization: Traffic
Type of utilization: Road tunnel
Client: Federal Republic of Germany, Free State of Saxony
Consulting Engineer: Müller+ Hereth
Examination: Prof. Dr.-lng. Dieter Kirschke
Construction monitoring: EIBS GmbH
Contractor: Ed.Züblin AG
Main construction method: Trenchless
Type of excavation: Drill-and-blast
No. of tubes: 2
Tunnel total length: Main tunnel 718.8 m, 685 m of which produced by trenchless means; Rescue tunnel 770.0 m
Cross-section: 135 m² main tunnel, 160 m² main tunnel with base invert, 184 m² in fault zone sector, 21 m² rescue tunnel
Contract Volume: approx. € 30 mill.
Construction start/end: 2004 to 2006
Opening: End of 2006