Geomechanics.io

  • Free Tools
Sign UpLog In

Geomechanics.io

Geomechanics, Simplified.

© 2025 Geomechanics.io. All rights reserved.

Geomechanics.io

CMRR-ioGEODB-ioHYDROGEO-ioQCDB-ioFree Tools & CalculatorsBlogLatest Industry News

Industries

MiningConstructionTunnelling

Company

Terms of UsePrivacy PolicyLinkedIn
    Projects
    Safety

    HS2 4,600-tonne viaduct slid over live M6: method and risk notes for engineers

    December 15, 2025|

    Reviewed by Joe Ashwell

    HS2 4,600-tonne viaduct slid over live M6: method and risk notes for engineers

    First reported on The Construction Index

    30 Second Briefing

    A 4,600-tonne, 315-metre HS2 viaduct deck was slid over the live M6 between Junctions 4 and 5 in a 17-hour operation, using a ‘fully restrained’ strand-jack system with Teflon pads to keep the motorway open except for an M42 slip closure. The east deck’s third and final launch, preceded by a 12-metre pre-shift under full closure, is thought to be the first fully restrained slide over a UK motorway and marks halfway completion of the M6 South viaduct. Each hollow double-box weathering steel deck sits on four pairs of concrete piers up to 9.9 metres high, with 82 precast slabs pre-installed and a 4.5-metre-high parapet planned for noise control.

    Technical Brief

    • Initial 12 m pre-shift under full M6 closure ensured both beam ends remained pier-supported during main slide.
    • Strand jacks provided controlled longitudinal movement while ‘fully restrained’ bearings limited transverse and rotational freedom above live traffic.
    • Teflon sliding pads reduced friction at the steel–concrete interface, lowering jacking forces and minimising dynamic effects.
    • Traffic management limited full M6 closure to one overnight window, with only the M42 slip shut during the main launch.

    Our Take

    HS2–linked pieces in our database increasingly highlight complex interfaces with existing infrastructure, and this M6 South viaduct slide by Balfour Beatty Vinci sits alongside recent HS2 items on green tunnels and road realignments as examples of the scheme’s reliance on heavy temporary works to keep strategic roads open.

    The decision to launch a 315 m deck over a live motorway at around 13 m/h indicates a preference for controlled incremental launching over longer full-closure windows, which other UK clients such as National Highways are likely to reference when planning future replacements on ageing structures flagged in Network Rail’s recent Control Period 7 challenge note.

    With 82 precast slabs and tall piers up to 9.9 m, this viaduct package reinforces how HS2 is sustaining demand for large precast and concrete operations at the same time as disputes over HS2-related compulsory purchase, such as Cemex UK’s High Court compensation case, underline the commercial exposure of materials suppliers around the route.

    Geotechnical Software for Modern Teams

    Centralise site data, logs, and lab results with GEODB-io, CMRR-io, and HYDROGEO-io.

    No credit card required.

    • Save and export unlimited calculations
    • Advanced data visualisation
    • Generate professional PDF reports
    • Cloud storage for all your projects

    Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.

    Related Articles

    CONEXPO mental wellness partnership: safety management lessons for site teams
    Infrastructure
    about 2 hours ago

    CONEXPO mental wellness partnership: safety management lessons for site teams

    CONEXPO-CON/AGG and The Utility Expo have formed a multi-year partnership with the American Foundation for Suicide Prevention to deliver construction-specific mental health education across North American worksites. The programme will embed AFSP’s evidence-based training modules on suicide risk, peer intervention and crisis response into toolbox talks, supervisor training and safety briefings. For contractors and asset owners, this signals growing expectation that mental health risk will be managed with the same structure and documentation as physical site safety.

    HS2 4,600t M6 viaduct slide: incremental launch lessons for project engineers
    Infrastructure
    about 9 hours ago

    HS2 4,600t M6 viaduct slide: incremental launch lessons for project engineers

    HS2 contractors have completed the final slide of a 4,600t viaduct section across the M6, moving the structure into position without a full carriageway closure in what they describe as a UK first. The operation used incremental launching techniques to shift the preassembled deck over live traffic, relying on carefully sequenced night-time lane restrictions instead of total shutdowns. For future motorway-rail interfaces, the method signals wider scope to build major spans offline and slide them into place, cutting possession times and temporary works demands.

    Hinkley Point C Bouygues–Laing case: safety and liability takeaways for engineers
    Infrastructure
    about 9 hours ago

    Hinkley Point C Bouygues–Laing case: safety and liability takeaways for engineers

    Bouygues Travaux Publics and Laing O’Rourke have pleaded not guilty to two alleged health and safety offences at EDF’s Hinkley Point C nuclear construction site, one involving a worker fatality. The cases, brought by the Office for Nuclear Regulation, relate to incidents during major civil works on the reactor complex, where heavy lifting operations, deep excavations and complex temporary works demand stringent CDM and nuclear site licence compliance. Contractors across UK megaprojects will be watching closely for any precedent on corporate liability for site safety management.

    Related Industries & Products

    Construction

    Quality control software for construction companies with material testing, batch tracking, and compliance management.

    Tunnelling

    Specialised solutions for tunnelling projects including grout mix design, hydrogeological analysis, and quality control.

    CMRR-io

    Streamline coal mine roof stability assessments with our cloud-based CMRR software featuring automated calculations, multi-scenario analysis, and collaborative workflows.

    HYDROGEO-io

    Comprehensive hydrogeological testing platform for managing, analysing, and reporting on packer tests, lugeon values, and hydraulic conductivity assessments.

    GEODB-io

    Centralised geotechnical data management solution for storing, accessing, and analysing all your site investigation and material testing data.

    AllGeotechnicalMiningInfrastructureMaterialsHazardsEnvironmentalSoftwarePolicy