Monitoring ground during backfilling in the sea
Cautus Geo is monitoring ground conditions with advanced instrumentation for the construction of a new container terminal in Kristiansand.
Problem statement
The Port of Kristiansand needs to fill in a lot of rock in the sea to establish a new container terminal at Kongsgård/Vige. The backfill is necessary for both a new quay and a new road. The ground conditions at the site are demanding. There is an old rock fill on the seabed that lies on top of a thick layer of clay. Under the clay is solid rock.
Solution
Cautus Geo installed a customised SAAV Subsea inclinometer. It was mounted vertically into the seabed and can record horizontal deformations in two axes along the entire 28-metre measurement string. The inclinometer will capture any sliding movements in real time. Data is sent continuously to Cautus Web. Limit values are set there. If they are breached, an alarm is sent to the project management so that work can be stopped and measures assessed.
The Port of Kristiansand IKS is one of the country's busiest harbours. 5,000 ship calls and 1.5 million passengers from ferries and cruise ships are big numbers. In addition, there is general cargo, fish, offshore and containers.
A new container terminal at Kongsgård/Vige is under construction and will be filled in at sea in 2026. This will be followed by construction work on a new quay with back storage. The new terminal will replace the current terminal at Lagmannsholmen in the city centre. There will be urban development. At Kongsgård/Vige, work will be carried out on land and in the sea where masses will be filled in. The new container terminal outside the city centre will be a modern terminal with increased capacity and efficient solutions.
Unique installation
The instrumentation is installed through the rockfill and further down into the underlying clay masses, anchored in rock. The inclinometer itself is set about two metres into the rock to ensure stable reference measurements. The pore pressure is also monitored.
The area closer to land will be filled in to make room for the new, modern terminal and the reorganisation of Vige Harbour Road.
New road and quay
The instrumentation established by Cautus Geo will provide the Port of Kristiansand with insight into and control over how the ground reacts during backfilling for the new harbour road and the first stage of backfilling for the new terminal.
The project also includes the establishment of a new water and wastewater network, two new high-voltage substations and new underground cable routes for future electricity supply to ensure shore power for ships.
Application area
Technology
In the case of large infills in the sea, it is important to monitor how the ground responds to the load. Instrumentation provides us with continuous data on deformations, enabling us to detect any movements early on and ensure safe execution of the work.
Design geotechnical engineer Carl-Fredrik Davidsen at Norconsult
Contact person
Switchboard telephone +47 990 96 580 or e-mail salg@cautusgeo.com
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