Länsimetro, track line construction contract RU27
The contract will include the construction of 17.5 kilometres of tracks, seven shafts and 32 connecting tunnels. The shafts are openings excavated to the ground surface about 600 m from the track line for ventilation, smoke extraction and pressure equalisation. In addition, the shafts act as emergency exits. The contract also includes the construction of connecting tunnel structures with fire barriers. The purpose of the connecting tunnels is to connect two parallel tunnels to each other and to ensure the safety of the metro in exceptional situations. There are connecting tunnels on the line every 150 to 170 metres. In addition, a total of 2,800 exit elements will be installed in both tunnels during the contract. The deck of the exit element also serves as a safe emergency exit from the metro. Inside the elements, 216 kilometres of cable protection pipes, almost 17 kilometres of drainage pipes and 16 km of stormwater pipes are being built. The line extends west from Matinkylä to Kivenlahti, and the construction is logistically very challenging.
GRK Suomi Oy