Monitoring the Opera Tunnel
Cautus Geo is monitoring ground conditions and securing the Opera Tunnel. The background is the construction of a new school with multi-purpose hall in Bjørvika.
Problem statement
The ground in Bjørvika in Oslo is unstable. A new school and multi-purpose hall totalling 15,000 square metres is being built there. The basement is being built below the water level. The Opera Tunnel runs directly underneath. It is a motorway tunnel with two tracks.
Solution
Cautus Geo monitors the ground conditions and tunnel runs. Several pore pressure gauges and borehole extensometers have been installed at the construction site. Inside the Opera tunnels, SAA deformation cables have been installed. They measure movements inside the tunnel with high accuracy. Data is continuously sent to Cautus Web. There they are continuously analysed. Limit values have been set. If they are exceeded, an automatic alarm is sent to the Norwegian Public Roads Administration, the contractor and Oslobygg KF, the developer.
The new school will be ready for use in the autumn of 2028. Groundwork started in January 2025. The developer is Oslo KF. Oslobygg KF is the client of Cautus Geo.
Cautus Geo monitors automatically and continuously. It will continue for five years. The instrumentation is extensive. In addition to deformation monitoring inside both tunnels, the ground outside is also monitored with pore pressure gauges and borehole extensometers.
The instrumentation ensures automatic and continuous measurement and sends data in real time to Cautus Web. An alarm has been set up with SMS and e-mail notification if changes occur in the ground conditions outside the heavily trafficked Opera Tunnel. The same happens if changes are detected inside the tunnels.
Cautus Geo has also previously secured the Opera Tunnelamong other things, when the museum trail was constructed in 2019.
The purpose is to control any movements on the tunnel. Two automatic settlement profiles have been installed, one in the eastbound and one in the westbound direction. Each of the profiles mounted on the walls is 216 metres long.
Bjørvika school and multi-purpose hall totalling 15,000 square metres. It will link the Sørenga area with Gamlebyen and Grønland.
Customer
Oslobygg KF
Year
2024 - 2029
Location
Oslo, Norway
Application area
Technology
It's all about safety. The work is taking place right next to the tunnel. The distance is down to 3-5 metres. This means that work must be stopped if there are changes in the ground conditions and pore pressure that affect the tunnel.
Project manager Tore Dahl in Oslobygg KF
Contact person
Switchboard telephone +47 990 96 580 or e-mail [email protected]
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