Peißenberg South B472

As part of the B472, Peißenberg Bypass, the low-lying section with the Peißenberg Tunnel, represents the biggest single scheme. The conception and production of this low-lying section took place under extremely constricted conditions in an industrial estate. The Federal highway dips into the 194m long encasement (tunnel) after following a cutting from the west, then runs in a trough cross-section at a depth of up to 7.30 m below the ground surface, underpasses a regional road and then rises towards the east to reach the prevailing level. The deep-lying section is devised for two lanes for vehicles (7.50 m carriageway width as well as additional emergency footpaths at both sides each 1.00 m wide). The clear height of the encasement amounts to 4.70 m, the overburden a maximum of 1.40 m. The industrial estate in the south of Peißenberg is located between two molasse spurs in a side basin of the Ammertal valley. It is filled with intermittent beds of moraine and alluvial deposits. In the vicinity of the deep-lying section the groundwater can rise to 5 m beneath the upper edge of the surface. However, as the new federal highway lies up to 7.30 m beneath the surface, a 388 m long groundwater trough is required here. Du ring the construction of the deep-lying section the groundwater had to be temporarily lowered with the aid of wells. As the groundwater also flows towards the north-east, the structure, which is aligned in an east-west direction, stands crosswise in the groundwater flow. In order to confine the groundwater damming up, groundwater collectors with disposal and absorbing wells were installed. The bored pile wall zone beneath the floor of the structure was also reinforced so that it was possible for the groundwater to pass below the structure. The encasement was produced by the bore pilling-top cover method and received a watertight base slab with walls rising at the sides. After creating the bore piles (88 cm diameter) excavation was undertaken down to a level necessary for producing the top cover. Subsequently the cover was shuttered, reinforced and concreted. In this way access to the industrial premises was again possible after a relatively short period of time. Then excavation below the cover could be carried out. The ensuing concreting operations for the base slab and the side walls as well as the intern al furnishings (installation of the road drainage utility lines and cable pipes as well as road construction work) also took place below the top cover. The trough cross-section between the encasement and the regional highway is open at the top. The side supporting walls were also produced using bore piling (120 cm diameter) at the encasement. Further activities were pursued in the same manner as for the encasement. The Installation of the operating technical equipment (pump unit to drain the deep-lying section, lighting, radio system and evacuation path markings in the tunnel, emergency call pillars in front of the portals) as well as the setting up of the traffic Installations took place after the roughwork operations were finished. The Peißenberg Bypass with the Peißenberg-South Tunnel and a further tunnel, the 383 m long Guggenberg Tunnel, became operational on December 11th, 2008.

Country: Germany
Region: Bavaria/southern Upper Bavaria
Tunnel utilization: Traffic
Type of utilization: Road Tunnel
Client: Federal Republic of Germany, Free State of Bavaria
Consulting Engineer: Staatliches Bauamt Weilheim; Ingenieurbüro EDR GmbH, Munich; Gackstatter Beratende Ingenieure, Stuttgart
Contractor: JV Xaver Riebel Bauunternehmung GmbH & Co./Bauer Spezialtiefbau GmbH/Gesa Elektrotechnik GmbH, Hilter
Main construction method: Open
Type of excavation: Cut-and-cover
No. of tubes: 1
Tunnel total length: 194 m (without ramps)
Contract Volume: 9.1 mill. Euro (roughwork), 1.7 mill. Euro (earthworks), 1.2 mill. Euro (operating technology)
Construction start/end: 2006-2008 (24 months)
Opening: October 2008