Extensive surveillance at Oslo Central Station

Home page Projects Extensive surveillance at Oslo Central Station

The ground conditions at Oslo Central Station are demanding. From 2016 and for several years, Cautus Geo carried out extensive monitoring there. Construction work and traffic flow were supported by real-time data.

Problem statement

The journey time from Oslo to Ski should be halved. The ground conditions at Oslo Central Station are demanding. Extensive construction activities in the area, which in the Follo Line project has been given the name "Introduction Oslo S", were necessary. In addition, the traffic density is high with many crossing tracks and preserved archaeological finds from the Middle Ages. In the years from 2016, monitoring of ground conditions and tracks was therefore initiated. Along the way, the monitoring was expanded several times. New locations and more tracks were monitored as construction work progressed towards the start of operations on the new railway in 2023. Everything that happened and could happen in the ground conditions during the work from Ekebergskrenten to Oslo Central Station was monitored and analysed in real time for several years.

Solution

Cautus Geo supplied most of the equipment for monitoring the ground conditions at Oslo Central Station from the start-up of the new Follo Line in 2016 until the line was taken into use in 2023.

All measurement results could be read continuously via web-based solutions. This gave Bane Nor, as the client, the opportunity to follow up the work in a secure manner. All measurements were reported in real time. This provides extra security during the construction of large structures in difficult ground conditions.

Cautus Geo packed the area with advanced measuring instruments. Measurement data was continuously analysed in real time. Slippage and displacement of mass would trigger an alarm.

The instrumentation was extensive:

27 laser cells on sheet piling.
23 vertical inclinometers measured deformations at depths of 11 and 53 metres.
13 horizontal inclinometers of between 10 and 50 metres measured longitudinal settlements.
Two total stations with measurements to over 40 prisms.
13 laser meters checked deformations inside the tunnel.
17 temperature gauges behind the sheet piling monitored frost.
200 tilt sensors were installed on railway tracks to monitor any settlements on the tracks.

Cautus Geo was also engaged by the AF Group at Sjursøya. They built the tunnel opening. Cautus Geo installed equipment to measure loads on load-bearing concrete structures.

It started with measurements on the sheet pile wall and automatic measurement to prisms. Later, it was expanded to include far more instruments and more comprehensive monitoring of the section.

Infrastructure in a historically important area

Between Oslo Central Station and the long two-mile tunnel, which forms the main part of the new 22-kilometre Follo Line, all work had to be adapted to other train traffic in and out of the capital. The railway is built with connections to several platforms.

The route runs in a covered culvert (tunnel) for 600 metres under parts of Middelalderparken. This part of the Follo Line runs through an area of great archaeological and historical significance.

The National Heritage Board, Oslo Municipality and Bane NOR collaborated on a solution for cultural conservation and trains in the historically sensitive area. This resulted in a new landscape plan. It means that the Medieval Park was expanded. The park's green areas were almost doubled when the construction work was completed.