UDK 02 – Concrete tunnel and soil tunnel

Bane NOR has awarded Veidekke Entreprenør AS the contract for soil tunnel and concrete tunnel in the Drammen-Kobbervikdalen project. This is an EPC contract, with an estimated value of 1.827 MNOK, and includes building a 290 meter soil tunnel and a 540 meter concrete tunnel (cut and cover).

Earlier this month, Veidekke signed the contract for a 6 km rock tunnel for the same project. The concrete and soil tunnels are to connect with this rock tunnel, making an approx. 7 km long double-track tunnel on the Vestfold line.

The latest contract was awarded after a Competitive Dialogue competition, in which four bidders were prequalified.

- We are very pleased with the competition, and that we had such highly qualified bidders, said Project Director at Vestfoldbanen, Lars Tangerås.
- The Competitive Dialogue process involved the bidders at an early stage, giving us the opportunity to find solutions that best meet Bane NOR's needs.

Concrete tunnel in open construction pit

An approx. 540 m long culvert in an open building pit with internal bracing will be built up to the loose deposits tunnel north of Konnerudgata. The excavation is partly under the water table, going down to depths from about 11 metres to about 21 metres. 

Ground conditions vary with up to 14 meters of clay over solid glaciofluvial deposits in the north and about 5 metres of sand over solid glaciofluvial deposits in the south. The glaciofluvial sediments are mainly friction aggregates (sand and gravel) with a fine particle content below 10%. 

Soil tunnel

To protect the local environment at Danvik, an approximately 290-metre tunnel is planned through loose deposits until a face is established in rock. The ground along the length of the loose deposit tunnel will mainly consist of friction aggregates. 

The loose deposits around the actual tunnel will have to be reinforced at ground level. The objective is to increase the strength/rigidity of the deposits and achieve sufficiently low permeability in the deposits around the tunnel to prevent water leakage and thus water table lowering along the tunnel. Once ground reinforcement is complete, the tunnel can be driven using a sequential drive method (short drive lengths and the use of shared cross-sections). 

Once the tunnel has been driven, a waterproof membrane and a permanent lining will be fitted. The permanent lining will be a reinforced concrete construction that covers the entire tunnel periphery. 

Main volumes concrete tunnel

Pipe piling	14,000 m2
Stabilisation with jet piles	15,300 m3
Internal tubular reinforcement	4,000 m
Excavation	110,000 m3
Concrete	12,900 m3
Reinforcement	2,500 tonnes

 

Main volumes soil tunnel

Drilling of injection and control holes	100,000 m
Injection from ground	15,500 m3
Injection from shafts	50,000 m3
Jet piles from ground	42,700 m3
Jet piles for shafts	1,950 m3
Excavation for tunnel	41,500 m3
Blasting rock in tunnel	10,000 m3
Temporary retention by drilling pipe screen in tunnel	18,400 m
Reinforcement for permanent lining	470 tonnes
Concrete in permanent lining	12,500 m3

 

Tracks and other railway engineering installations are not included in UDK 02.