The Ardersier Energy Transition Facility is a major new port facility being constructed in northern Scotland to support future large-scale deployment of offshore wind farms. GEO-Instruments has installed a large excavation monitoring scheme to support the construction of the new quay.
The new port is located on the Moray Firth near Inverness. Built in a natural, sheltered harbour, with easy access to North Sea, the port is ideally loacted for supporting fixed and floating offshore wind projects.
When complete, it will be the largest dedicated offshore wind deployment port facility on Scotland’s North Sea coast.
The port will comprise a 659-metre quay wall, including a main quay at 420 metres long that will be able to accommodate multiple berths, and an additional 150 acres of space for assembly and storage of wind farm components.
Depending on the evolving needs of the industry, there is space for expansion, with a potential 1km of additional quay wall.
Building the new harbour required a large excavation and the construction of two walls either side. The front wall and anchor wall are connected by arrays of tie rods to reinforce the harbour.
The walls are likely to exhibit movement during excavation, dredging and at high and low tides. It is vital to accurately monitor this movement to confirm it falls within expected limits and to verify the performance of the tie rods.
GEO‑Instruments has implemented a geotechnical monitoring scheme built around In-Place Inclinometers (IPIs).
The monitoring scheme requires twenty-four IPIs installed into piles at regular intervals along the front and anchor walls of the excavation. Depending on the area and monitoring requirements, the instruments are installed to between 15 and 35 metres depth.
Each installation consists of a string of sensors fixed at intervals down the borehole, forming a profile that measures how the ground is moving horizontally at different depths.
The design and installation of each IPI was a careful process. Comprised of 1-metre and 2-metre-long sections, the IPI segments were fitted in precise configurations, allowing for higher or lower resolution profiles at specified depths.
The use of fewer, longer segments at less critical sections also provides a significant cost saving for the client.
IPIs measure small changes in tilt at each sensor location. These changes are aggregated and converted into lateral displacement.
Unlike manual inclinometer surveys, which require equipment to be lowered into the borehole each time, IPIs stay in place and record data automatically.
Using IPIs over manual Inclinometers prevents issues with needing regular access to the monitoring locations and automatic measurement means readings can be taken at much higher frequencies.
These setups are most useful in applications where continuous data is needed rather than occasional snapshots.
3D monitoring of the capping beam is also undertaken on site using Automated Total Stations and monitoring prisms. Measured movement of the capping beam can be easily compared against data from the IPIs.
The monitoring data is automatically collected and transmitted using wireless nodes at each location and two central Gateways to communicate with all sensors. Data is then sent and displayed in QuickView where it is reviewed by the project team.
Engineers can look at profiles, compare movement between different areas of the site, and establish how the walls respond at different excavation stages.
Detailed spatial graphs are set up for each IPI location, showing the depth and extent of horizontal movement.
Automated alerts are configured so that if movement exceeds specified thresholds, the team is notified and can investigate as early as possible.
Major dredging works in the harbour are now complete and further landside works will continue through this year.
GEO-Instruments is excited to be involved in this major project and to help build part of the UK’s future sustainable energy supply.
Read more about our previous dock monitoring projects.