Metro Construction, LU6E section, the Karhusaari Tunnels

Urban Metro
Helsinki, Finland

The Länsimetro (West Metro) project is a new transport link between Helsinki and Espoo in Finland. With a scheduled transport capacity of 100,000 passengers per day, it is directly linked to the only operated line, which is 21 km long.

Basic information

Objednatel:

Länsimetro OY

Projektant:

KalliosuunnitteluOY Rockplan Ltd.

Doba výstavby:

04/2011 – 10/2013

Characteristics

Länsimetro (West Metro) is a new transport link between Helsinki and Espoo completely underground at a length of 14 km. The LU6E – Karhusaari track section consists of a total of 2,613 m of mining carried out in hard granite using the Drill & Blast method. Mining of three technological chambers with ventilation shafts in each of them and seven tunnel junctions are also part of the delivery. The section route is partly under sea level and it proceeds under, among other things, the foundations of the Nokia headquarter buildings. The most challenging task was to excavate sections under the sea level, in areas sensitive to seismic load due to blasting works, along with a considerable amount of grouting works. 

Project in Numbers

  • 36,2 - 42,1 m2 Tunnel profile
  • 140 000 m3  Volume of excavated material
  • 26 - 35 m Depth of 3 shafts
  • 55 000 m  Bolting equipment
  • 1 360 000 Kg  Cement

Exceptionality of the Structure

Mining under sea level. Mining in a seismically sensitive area under the foundation of the Nokia headquarters. Award by the contracting authority for the safest construction site of Länsimetro.