Rock Mechanics and Tunneling Design

Stockholm Metro – Blue Line Extension to Nacka

Stockholm metro’s blue line is being extended from Kungsträdgården, with new terminals at Nacka and Sockeplan. The track length of the extension is 11 kilometers, along which 5 new metro stations will be built. Rockplan’s responsibilities in the project include rock mechanical design and engineering geology at Nacka and Sockenplan, as well as engineering geological reports from Gullmarsplan, Sofia, Hammarby Canal and Sickla.

Construction of the blue line extension began in 2019 and the metro is intended to reach Nacka and Sockeplan by 2030.

South-Hermanni Underground Parking Facility

The South-Hermanni parking facility serves residential and commercial properties in the area. There are 336 parking spaces, as well as five stairwells and four elevators to the surface level. The design of the parking facility has considered the landscaping and fit of the above-ground entrances as part of the surrounding urban structure.

Vuosaari Transportation Tunnels

Rockplan designed Vuosaari Harbor’s Porvarinlahti road tunnels and Labbacka railway tunnel in cooperation with Finnmap Infra Oy.

The 1,600-meter-long submarine road tunnel in Vuosaari is approximately 25 meters below sea level at its deepest point. The road tunnel was opened in 2007 and is currently the third longest road tunnel in Finland. The tunnel leads to the beginning of Ring Road III in Vuosaari Harbor.

The 600-meter-long Labbacka railway tunnel is part of the 19-kilometer-long Vuosaari freight port and runs under the Labbacka Natura 2000 environmental site. After Labbacka, the track crosses Porvari Bay.

In 2008, the Vuosaari Harbour and its transportation organization received the Finnish Association of Civil Engineers’ RIL Award, which is given in recognition of an project whose design and implementation have demonstrated excellence in the construction industry.

Paloheinä Public Transportation Tunnel

The Paloheinä tunnel is a traffic tunnel running underneath Helsinki Central Park for more than a kilometer. Rather than a new bus line passing through the park, it was decided to run it through a tunnel under the park and preserve the recreational uses on the surface. Currently, the tunnel is only used by public bus transportion, but the design has also accounted for possible future tram traffic. The main 560 bus line using the tunnel carries passengers between Vuosaari and Myyrmäki.

Completed in 2015, the Paloheinä tunnel fell short of the budget by more than 6 million euros. The savings arose when the plans were simplified, and a single-pipe tunnel was built instead of a two-pipe tunnel. The rock excavated during the construction of the tunnel was used in the area for the rehabilitation of the Paloheinä recreation and for the construction of the Kuninkaantammi area.

Kluuvi Parking Facility and Civil Defense Shelter

The Kluuvi parking facility was excavated in the bedrock under an existing service tunnel and about 26 meters under the existing Porthania building. When completed in 2000, the Kluuvi parking facility was the second largest underground parking facility in Helsinki. The facility has 725 parking spaces in two halls and three floor levels.

There is pedestrian access from the parking facility to the Kluuvi shopping center and the University of Helsinki metro station, connecting parking and civil protection with the surrounding Helsinki area. If necessary, the space serves as a civil defense shelter for 7,500 people.

Kakolanmäki Wastewater Treatment Plant

A 471,000 cubic meter rock field was excavated near the center of Turku for construction of the Kakolanmäki Wastewater Treatment Plant. When completed, the wastewater treatment plant replaced five old treatment plants and also reduced the region’s effluent load to the sea by 30–50%.

The sludge separated during the treatment produces biogas, which is used for district heating. The Kakola Heat Pump Plant also uses the waste heat from the treated wastewater.

The adjacent, valuable old buildings housing the Kakola Prison, created challenges for the excavation. Design and construction of the wastewater treatment plant particularly considered the location in the urban environment and near our valuable archipelago.