Tunnels and underground structures

Brief description
and characteristics of the project

The Meyrin cut-and-cover project was part of the final stages of work on the Tram-Cornavin-Meyrin-CERN (TCMC). The aim was to improve traffic flow in the village of Meyrin (25,000 v/d) and to build the extension of the tram towards CERN. The route de Meyrin was buried by means of a covered trench. The tram tracks were built on the backfilled slab.

The works involved the creation of :

  • A 715-metre-long cut-and-cover tunnel,
  • Two 95-metre-long traffic hoppers,
  • An area of technical premises dedicated to the structure’s operating systems,
  • Two 3.50-metre traffic lanes,
  • Three SOS niches
  • Three emergency exits

The main constraints of the project were as follows:

  • Maintaining access to the village centre for shops and emergency services despite the cramped nature of the site,
  • Maintaining traffic flow on the existing cantonal road during the works,
  • Existing networks to remain in service
  • Proximity to the plumb lines of existing buildings.

Mission

As a civil engineer and geotechnician in a multi-disciplinary consortium, GEOS carried out a complete project management mission including the following services:

  • Preliminary design,
  • Final design,
  • Application for planning permission,
  • Invitation to tender,
  • Execution project,
  • Construction management,
  • Commissioning and completion.

GEOS Ingénieurs Conseils, as leader of the GETM consortium, also carried out the following coordination tasks:

  • Administrative management of the project.
  • Coordination of the technical design of the structure.
  • Supervision of the project’s financial management.
  • Management of technical responsibilities: civil engineering, geotechnics, geology, waste management and special works.
  • Technical and administrative management of subcontractors for electromechanical equipment required for user safety, ventilation, lighting, signalling, video surveillance, fire detection and defence, acoustics and landscape architecture.
  • Project Owner : Etat de Genève (Suisse)
  • Mission : Maîtrise d’œuvre complète
  • Cost of the works : 70’000 kCHF
  • Cost of the mission : 4’400 kCHF
  • Mission date : 2005-2011

Technical specifications:

  • Moulded walls 60 cm and 80 cm thick (17,800 m2),
  • 80 cm diameter bored piles (2,000 ml),
  • Concrete (15,950 m3), reinforcement (1,250 tonnes),
  • Temporary nailed wall supports (400m2),
  • Top-down construction (27,500 m3 of earthworks),
  • Open and lined trenches (56,100 m3),
  • Pavement structure (6,000 m3), bituminous surfacing (1,970 t),
  • Installation of sewerage and drainage networks (24,500 ml),