In close cooperation with Ramboll, NGI has designed and prepared tender documents and followed up contracts related to the following basic work at the new Government Quarter in downtown Oslo.

Preparatory contract tenders

  • Mapping and evaluation of neighbouring buildings
  • Deformation and settlement monitoring
  • Vibration measurements
  • Geotechnical investigations, groundwater
  • Pipe-pile wall and work protection of existing excavation in rock

The contract tender for ground works

The contract tender for ground works has mainly consisted of:

  • Blasting and discharge of open excavation pit of approx. 100 000 m3.
  • Stability support with bolts, braces, beam-grid and sprayed concrete.
  • Waterproofing, pre- and post-injection and sprayable membrane.
  • Demolition of concrete structures in existing rock cavern.
  • Profile expansion of tunnels in existing rock cavern.
  • Blasting for new rock cavern in connection with existing one.
  • Boring of pipe-pile wall. Mounting of pillows and braces.stag
Oppstart av byggegrop article

Start of excavation pit
   

Challenging ground conditions

The bedrock underneath the Government Quarter consists mainly of alum slate, which implies particularly demanding ground conditions for the project includes. This involves special considerations related to rock support, the environment, characterization of shale to determine landfill waste classification, and waterproofing to limit chemical reactions in the shale.

NGI has played a key role in the construction phase, where 3-4 employees have followed up geoscientific tasks full-time during the construction process.

Svartskif sampl Bolte sikring

Sampling for analysis of black slate (left). Design and follow-up of construction in rock with comprehensive stability control (right).