This article analyses the report by the Health & Safety Executive (HSE) on the collapse of some Heathrow Express Line tunnels in October 1994, during the line's construction. The New Austrian Tunnelling Method (NATM) was proposed for design and construction of the line's underground stations, and was adopted after a successful trial. The client, the British Airports Authority (BAA), chose an approach using 'performance specifications', which made the contractors responsible for commercial and technical risks. The collapse affected three tunnels in the Central Terminal Area (CTA), which were being constructed at the time. A few days before, serious distress in the tunnel linings became evident, and the stability of the tunnel system went out of control. There was extensive and worsening cracking and spalling, and severe damage and movement, especially in the inverts of the concourse tunnel. The tunnel collapses occurred over several days, then the buildings above slowly collapsed. The report found many errors in design, poor construction and quality control, and a lack of effective engineering management of the project. It especially criticised the design and construction of the central invert joint, which led to other construction defects. The HSE found that the tunnel monitoring instrumentation indicated continuing movement in the tunnel and ground for some months before the collapses.

  • Availability:
  • Corporate Authors:

    Miller Freeman

    Calderwood Street
    London,   United Kingdom  SE18 6QH
  • Authors:
    • Anderson, J
  • Publication Date: 2000-8


  • English

Media Info

  • Features: References;
  • Pagination: p. 20-2
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00799862
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Oct 6 2000 12:00AM