The design of the Crossrail tunnels in UK

This paper will focus on the use of fibre reinforced concrete on the Crossrail project in the UK. Crossrail (now named The Elizabeth Line) is a new railway running from West to East under the centre of London. This railway runs for approximately 14 km underground and five of the new stations were constructed with permanent sprayed concrete linings. Fibre reinforced concrete played a prominent role in all of the tunnelling - both for the segmental linings and the sprayed concrete tunnel (SCL) linings. Having reviewed the context of the project and the state-of-the-art in tunnel design at the time of the design, this paper will describe the design approach for both the TBM and mined tunnels and their fibre reinforced linings. While the segmental lining design followed a conventional approach, the SCL tunnels adopted an innovative design with the first major application of permanent sprayed concrete in the UK and featured the first use of a spray applied waterproofing membrane (SAWM) on a major project in Europe. Performance during construction will be reviewed and conclusions will be drawn on what can be learnt from the mega project.