DRAMMEN TUNNEL ON THE OSLO-TØNSBERG RAILWAY LINE, DRAMMEN-KOBBERVIKDALEN SECTION
EUR 187 million (soil tunnel- EUR 47 million)
Design speed: 200-250km/h.
The 290 m tunnel is a subsection of the approximately 7 km long tunnel in Drammen, where the geotechnical conditions are extremely complex:
– The existing soils are glaciofluvial deposits, consisting mainly of dense sand and gravel and containing boulders of different sizes.
– Most of the tunnel will be excavated below the water table.
– The tunnel will be excavated under a densely populated area with a crossroads and buildings where overburden heights are less than the tunnel diameter.
– Subsection tunnelled in mixed soil and rock ground conditions (location that requires a special design).
Large span tunnel (14 m width) excavated using a sequential method (SEM) with intensive ground treatment.
Feasibility study, preliminary tender design with further technical development that included 2D and 3D models for tunnel design in soil, 3D geometric model (BIM), etc; a 3D geometric model including ground treatments (drilling, ground treatment volumes, etc), support systems, treatment shafts, and lining. Independent review of the tunnel section detailed design and supervision of the works.