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Munich Metro U3, Line 3 North, Contract Section 2

A new Metro rail link is being set up in the north of the Bavarian capital Munich between the Olympia-Einkaufszentrum (Olympia Shopping Centre) Underground Station and the Moosach S-Bahn Station. The client, the regional capital of Munich represented by the Construction Department Metro Construction, commissioned the JVU-Bahn Linie 3 Nord, contract section 2 to undertaken the work in August 2004. Contract section 2 by and large consists of 2 Metro stations (Moosach and Leipziger Straße, which are connected by twin tubes as well as the link between the tunnels and the existing Olympia-Einkaufszentrum Underground Station. The stations were produced by the diaphragm wall/top cover construction method with the diaphragm walls integrated in the groundwater level as so called troughs. The two parallel running tunnel tubes were driven one after the other from Moosach Station by means of shield driving with a slurry supported/ compressed air supported face. The northern tunnel section (track 1) was produced first then the southern one (track 2) with the same machines. After 509 m the drives reached Leipziger Straße Station. There the TBM was pushed through the previously built station. Then the 694 m long second part-section was produced extending to the Olympia-Einkaufszentrum Station. After each drive the machine's core was retrieved and the shield skin remained in the subsoil. The shield machine was designed by Herrenknecht as a hydro- shield. The excavated diameter amounted to 7.35 m. Bentonite was applied to transport the excavated material and to support the face. The shield was devised as a two-part structure with bolt connections consisting of a cutter sect ion and a central section. The cutting wheel was designed as an open spoked wheel with two directions of rotation and consisted of 5 arms. Special cutters were used as extraction tools for the medium-dense, dense and extremely dense bedded quaternary gravels. In the second tunnel section the layer boundary rises between quaternary and tertiary. Towards the end the entire cross-section runs in tertiary with silt and clay as well as sand layers with partially confined groundwater. The cutting wheel was fitted with cutters to tackle this soil formation. The expected high abrasiveness was counteracted by means of corresponding wear protection measures. The segments were designed to produce a ring with 6 elements and a keystone with left-hand and right-hand conic rings. The segments were produced in concrete quality C 35/45 with a thickness of 40 cm and 1.50 m ring thickness. The EPDM sealing frames are designed to cope with water pressure of up to 3 bar. The rings were coupled together with a cam and pocket arrangement in the ring joints. The distribution of pressure in the ring joints was attained by installing 2 mm thick hard fibre boards in the annular joints. An emergency exit has been set up between the Leipziger Straße Stat ion and the existing Olympic Shopping Centre (OEZ) Station. Prior to beginning the driving operations bored piles were created in the middle of the two tunnel routes, which overlap the tunnel cross-sections. The piles in the overlapping area were designed as unreinforced sealing piles. In this way watertight areas were created after the passage of the TBM, in which shafts were excavated in order to produce the connection to the tunnel tubes.

 

  • Country: Germany
  • Region: Bavaria, Munich
  • Tunnel utilization: Traffic
  • Type of utilization: Metro Tunnel
  • Client: Regional Capital of Munich, Construction Department Metro Construction
  • Consulting Engineer: WTM Engineers München GmbH (designing the stations),  PSP Consulting Engineers GmbH {designing the tunnels)
  • Test engineer: Dr. Linse und Partner, Munich
  • Contractor: U-Bahn Linie 3 Nord, Baulos 2 JV: Wayss & Freytag Ingenieurbau AG (technical management), Hochtief Constructlon AG (commercial management), Bauer Spezialtiefbau GmbH
  • Main construction method: Trenchless
  • Type of excavation: Shield machine(SM)
  • Lining: Reinforced concrete segments
  • No. of tubes: 2
  • Tunnel total length: 2 x 1203 m
  • Cross-section: 39.60 m² (tunnels)
  • Contract Volume: 73.60 mill. Euro
  • Construction start/end: September 2004 till September 2009
  • Opening: 2010