DRAMMEN TUNNEL ON THE OSLO-TØNSBERG RAILWAY LINE, DRAMMEN-KOBBERVIKDALEN SECTION

Key facts

The project is part of a 10 km double track section.

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.