The construction of Crossrail’s first permanent sprayed concrete lined (SCL) tunnels on the project is now underway at Blomfield Street in the City of London.The Liverpool Street Station Advance Works team is creating a 55m long cable tunnel and shaft for the utilities associated with the new Crossrail station. Work started on the cable shaft in June.
The tunnel is being constructed in an incredibly confined space in and around existing utility and London Underground services and precision working is paramount.
The tunnel is around 4m high and 3.5m wide and is being excavated 24-hours a day, Monday to Friday. The team is using a 1.5 tonne excavator for the bulk excavation of the tunnel and are then ‘trimming’ the surface of the excavation with a remote controlled machinery. A shotcrete robot is used to apply steel fibre reinforced sprayed shotcrete which creates a 275mm thick tunnel lining.
Earlier this year, contractor BBMV JV completed two temporary sprayed concrete lined (SCL) tunnels at Finsbury Circus. These are being used for compensation grouting, part of Crossrail’s measures to control any ground movements that could result from our tunnelling.
The SCL works are being undertaken by BBMV JV (Balfour Beatty Civil Engineering, Alpine BeMo Tunnelling, Morgan Sindall and VINCI Construction) as part of the C510 contract – Early Access Shafts and Spray Concrete Lining works for Whitechapel and Liverpool Street station tunnels.