Virngrund tunnel

Virngrund tunnel
use	Road tunnel
traffic connection	Federal motorway 7
place	Ellenberg
length	468 m
Number of tubes	2
construction
building-costs	28.2 million DM (≙ 25.7 million euros)
start of building	5th February 1985
completion	18th December 1987
location
Coordinates
North portal	49 ° 1 ′ 19 ″ N , 10 ° 11 ′ 48 ″ E
South portal	49 ° 1 ′ 4 " N , 10 ° 11 ′ 50" E

Map with all coordinates: OSM | WikiMap

The Virngrund tunnel is a 465 or 468 meter long tunnel of the federal motorway 7, northeast of Ellwangen on the Ellenberg district .

history

During the construction of the Würzburg - Ulm motorway section in the 1980s, there was no avoiding tunneling through the Hornberg , the largest elevation in the Virngrund forest area at 579 m above sea level. NN . The first plans envisaged a crossing further east, after which the motorway would have been led in a deep cut over the ridge of the Hornberg. After residents protests, this plan was discarded and a tunnel solution was chosen. The tunnel was erected on February 5, 1985 and its shell was completed by March 31, 1987. It was opened to traffic on December 18 as part of the final section of the A 7 from Heidenheim to Feuchtwangen .

The tunnel will be renovated from May 2019 until probably September 19, 2020. The renovation work includes the trades concrete, fire-fighting water pipeline, drainage, emergency basin and operating technology. One tunnel tube is blocked and all traffic is directed through the other tube.

geology

The pre-cuts and portals of the Virngrund tunnel were adapted to the existing terrain. The parlor sandstone had to be drilled through, which consists of a sequence of sand and claystone layers that are distributed irregularly over the entire cross-section of the tunnel. In some places the rock had to be loosened with blasting, elsewhere the mountains could be removed directly with excavators. Since the cap of the edge zone of the ridge is a sliding block of the marl marl , complex construction pits and embankment protection measures were necessary on the north flank.

Construction

When tunneling new knowledge is turned to Austrian tunnel builders: A anticipatory top heading was allowed a limited distance the gullet - and follow Sohlausbruch and a rapid ring closure. All excavated areas had to be immediately secured against the weather and statically stabilized with shotcrete, welded wire mesh and mostly with steel arches.

Data

The two tubes of the Virngrund tunnel are separated by a 13.6 m thick earth core. They have a length of 465 m (direction Ulm) and 468 m (direction Würzburg). The lanes of the federal motorway are each 3.75 m wide, the accompanying hard shoulder ends in front of the portals. The tunnel tubes are 4.5 m high.

In the middle between the two main tubes, a third tunnel tube was inserted as an escape route and passage for rescue vehicles. This tube can be reached from the center of the tunnel via an escape tunnel.

The construction costs of the Virngrund tunnel were:

Tunnel shell construction: 22.5 million DM (corresponds to 20.49 million euros today)
Technical facilities: DM 5.5 million (corresponds to EUR 5.01 million today)
Company building: 0.2 million DM (corresponds to 0.18 million euros today)
Total costs: 28.2 million DM (corresponds to 25.68 million euros today)
Refurbishment 2019/2020: 28 million euros

Individual evidence

49.01941 10.1972Coordinates: 49 ° 1 ′ 10 ″ N , 10 ° 11 ′ 50 ″ E

[1] ttps://www.radio7.de/zuhause/news/am-virngrundtunnel-auf-der-a7-starten-am-freitag-die-bauarbeiten

[2] ttps://www.swp.de/suedwesten/landkreise/lk-schwaebisch-hall/vollsperrung-virngrundtunnel-baustelle-doch-frueher-verbind_-tunnel-an-der-a7-bei-ellenberg-wird-nochmal-komplett - locked-50529865.html

[3] ttps://www.swp.de/suedwesten/landkreise/lk-schwaebisch-hall/vollsperrung-virngrundtunnel-baustelle-doch-frueher-verbind_-tunnel-an-der-a7-bei-ellenberg-wird-nochmal-komplett - locked-50529865.html