Strabag UK is carrying out an artificial ground freezing trial at Sizewell C nuclear power station in Suffolk.
Artificial ground freezing is a construction technique used when building tunnels and shafts to provide temporary earth support and groundwater control when other conventional methods are not feasible.
It involves drilling and installing steel freeze pipes into the ground at a regular spacing around the outside of the future excavation pit and circulating a brine freezing solution through the pipes.
In its trial, Strabag is using benign salt water as a cooling fluid in a closed-loop freeze pipe system that turns groundwater to ice to create a frozen wall around the excavation area.
The waterproof enclosure can then remain in place until excavation works have been completed and permanent basement walls constructed.
The brine solution can be recovered from the pipe system to be reused on other projects.
Strabag and its civil engineering subsidiary Züblin have already used this method during the construction of the Silvertown Tunnel in London.
Strabag UK’s managing director, Simon Wild, said: “As a business, we pride ourselves on developing innovative solutions to the challenges of delivering major projects. Together with Züblin, our industry-leading ground engineering experts, we are committed to working with Sizewell C and all stakeholders to take full advantage of the benefits that this ground-freezing approach can deliver in terms of programme improvement and minimising the impact on the natural environment.”
Sizewell C is a multi-billion project led by French energy company EDF to build a 3,200 MWe nuclear power station with two EPR reactors in Suffolk. The Civil Works Alliance, comprising Laing O’Rourke, Bouygues and Balfour Beatty, was appointed to deliver the initial civil works.
