The HS2 rail line will be partially built using giant 3D printing technology under plans to cut costs, disruption and emissions.
Reinforced concrete structures installed as part of the 225mph railway will be printed on site by a giant robotic arm to avoid the inconvenience of transporting precast slabs by road.
In the first system of its kind in the UK, the mobile machine will squirt concrete laced with super-strong graphene through a nozzle, following a digital design pattern to create the structure from the bottom up.
The technology will initially be used by HS2 contractors building tunnels on the route out of central London as part of a trial beginning in spring before possibly being employed elsewhere on the line. It could lead to a 50 per cent reduction in carbon emissions for the whole project, it is claimed.
Some communities along the route are angry over the impact of HGVs used to transport equipment and material to and from work sites.
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In March, councillors in Buckinghamshire — one of the most contentious parts of the route — rejected plans from HS2 to send lorries through part of the county. Previous warnings had been made over residents facing “complete chaos”, with property and vehicles being damaged and cars queuing on small village roads.
The technology behind 3D printing is well established in many sectors of the economy including manufacturing and medicine. The first 3D printers for construction emerged in the 2000s and have since been used to build houses, offices, museums and even a bridge in Spain.
The HS2 system — called printfrastructure — will be used by the construction companies Costain, Skanska and Strabag, which are jointly building the tunnelled sections between central London and the M25.
The 3D printing machine is a five-tonne mobile robotic arm, which has a 3m by 3m reach and follows a preset programme to lay-out concrete structures line by line. It will initially be used to build part of the retaining wall for the main HS2 line out of Euston station as well as material stores — temporary buildings used to hold construction materials. The microscopic strands of graphene in the concrete used by the machine are only several atoms thick and will run through the concrete “like stripes in a stick of rock”, the public company has said. Graphene is about 200 times stronger than steel, which is usually used in reinforced concrete.
The government body said that the system, which was developed by ChangeMaker 3D, a company in Worcestershire, would reduce the overall quantity of concrete needed for the project by creating a closer physical link between the production process and the work site itself.
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The company also said that it would lead to greater flexibility over construction and possibly a shorter build time as well as the cuts to emissions.
Although the technology has yet to be used in a trial, HS2 believes that it could be used for multiple structures along the route including bridge parapets, staircases, walls, columns and station platform segments. HS2 is under pressure to rein in costs and speed up construction because of concerns over the rate of progress over the project, which will ultimately result in a 330-mile Y-shaped rail network linking London, Birmingham, Manchester and Leeds. It is forecast to cost as much as £88 billion, up from a previous estimate of £56 billion in 2015.
Work started on the first phase of the line between the capital and Birmingham last year. The northern leg of HS2 is less certain. Ministers are committed to building the line to Manchester but the eastern leg — a 120-mile link from Birmingham to Leeds — is subject to a separate review that will be published in autumn.
Rob Cairns, the HS2 innovation manager, said: “With a build programme spanning the decade and across the country, the project is creating an ideal environment to develop technologies with the potential to transform how major infrastructure is built.”
