Tunnel Nollinger Berg
The Nollinger Berg Tunnel has to be constructed as part of the A 98 Upper Rhine Motorway Weil am Rhein-Waldshut, construction section Waldhof-Rheinfelden/Karsau and the Rheinfelden cross-link with Switzerland (A 861) 2 separate tubes with an approx. 30 m gap in between axes are foreseen, although initially only the east tube is being constructed. The maximum overburden amounts to approx. 65 m compared with a minimum figure of 15 m. The clear cross width comprises 2 lanes (each 3.50 m), the verges (0.25 m) and the emergency footpaths (each 1.0 m). The clearance height amounts to 4.5 m. ln the drained zone, a standard cross-section with open base with an excavated area of approx. 87 m² as well as the emergency bay cross-section (length 40 m) with an excavated area of approx. 115 m² has to be built over a distance of 480 m. ln the zone with pressure water, the standard cross-section with roughly 99 m² has to be created over 685 m. At the transition from the drained section to the one with pressure water, a dam ring is installed as a bulkhead in order to avoid the draining effect of the southern part of the tunnel influencing the Underground water reserves. In addition, a cross-over with the waste air centre, a retention basin for precipitation in front of the south portal and an operations centre at the north portal have to be constructed. Geologically speaking, the ground and in turn, the heading methods, can basically be divided into 2 sections:
- from the south portal to approx. tm 520, mainly chalky-dolomite layers of the upper shell lime and the letten keuper are encountered, in the form of undisturbed mainly solid and largely stable ground
- from approx. tm 520 to the north portal at tm 1,260 m, leached gypsum keuper marl predominates, which more or less has crumbled to create deformations and the build up of water pressure.
On the basis of the geological and hydrological conditions which were encountered, a heading using the shotcreting method was chosen for the tunnel excavation. The overall cross-section is to be carried out in 3 part-excavations (crown, bench and in part, base invert). In the southern half, the ground is mainly loosened by means of "gentle" blasting. This section is produced as a drained tunnel without base invert with umbrella waterproofing. In the northern part, the ground is removed by excavators. In this section, a base invert is required as it has to be constructed to resist pressure water.
- Country: Germany
- Region: Baden-Württemberg
- Tunnel utilization: Traffic
- Type of utilization: Road tunnel
- Client: Bundesrepublik Deutschland, Land Baden-Württemberg
- Consulting Engineer: Bung Beratende Ingenieure, Müller+ Hereth
- Contractor: Max Bögl GmbH & Co. KG; Walter Bau AG
- Main construction method: Trenchless
- Type of excavation: Drill-and-blast
- Lining: In-situ concrete
- No. of tubes: 2
- Tunnel total length: 1,268 m including a 1,205 m mined section
- Diameter: 87 m² (drained section), 99 m² (watertight section), 115 m² (breakdown bays)
- Contract Volume: approx. 50 mill. DM
- Construction start/end: 2/1998-2/2000
- Opening: 2000