BMG GmbH & Co. KG - Keithstrasse 2-4 - D-10787 Berlin | Tel: +49 (0)30 2100220

PDB 66

Construction Project
North-South Connection Berlin-Press. Caisson Lenné-Dreieck
Location
  • Berlin
Client
  • DB Projekt GmbH Knoten Berlin
Planning
  • IVZ-Ingenieurgemeinschaft for the planning of transport facilities in the centre of Berlin, Emch und Berger, Schüssler-Plan, DE-Consult
Investment volume
  • approx. DM 21.0 million
Construction period
  • April 1996 to July 1997
Contracted services for BMG
  • Section 55.8 HOAI-General construction management
Structures constructed
  • Construction of the caisson (L = 42 m) as four-cell tunnel cross-section with an excavation volume of 40,000 m³
  • Caisson cross-section (W/H = 48.00/14.20-20.00 m)
  • Lowering depth 18.50 m at a lowering rate of 0.30 to 1.00 m/day
  • Caisson covers 5.00 m
  • Caisson surface areas 2,000 m²
  • Lowering weights about 36,000 t
Special features
  • Construction of an earth model in the approach cutting on well-compressed subgrade
  • Concreting of the lowering chamber and the wedge-shaped edges with 8 cm overcut
  • Concreting of the four-cell tunnel structural parts and integration of airlocks for people and material in the structural parts for supplying the pressurized workplaces
  • Excavation of the earth model under atmospheric conditions before beginning lowering
  • Lowering of the construction using flushing guns and pump removal of the ground emulsion
  • Filling the undercut during the lowering procedure using bentonite as lubricant
  • Working under pressurized conditions at a pressure of up to 2.3 bar for protection from groundwater
  • Fixing of the caisson after reaching final depths, protected by sealed beds and sealed walls, by demolition of the caisson front walls and sealing of the standard joints
  • Lowering precision target/actual = 15/5 cm
  • Acceleration of the lowering process by using 6,000 t of water ballast/11,000 t soil extra load
Utilization
  • Railway tunnel for DB AG
Construction
  • Construction of the caissons using concrete impervious to water
  • Concrete used in construction 18,000 m³ and reinforcing steel used in construction 2,500 t