Crossrail contract C300
Western Running Tunnels
(Royal Oak to Farringdon)
Crossrail’s Western Tunnels Contract is one of the largest of the Crossrail contracts. At peak production the TBMs can each advance up to 40 metres in a day excavating in excess of 3,000 tonnes and installing 575 tonnes of concrete tunnel lining rings.
The western tunnels (C300/410) work comprises two 6.2m internal diameter bored tunnels, each 6.5km long between the Royal Oak portal, which is west of Paddington Station, and Farringdon Station, and the sprayed concrete lining (SCL) station tunnels at Bond Street (BOS) and Tottenham Court Road (TCR) and the Fisher Street (FS) cross over tunnel, including ticket hall shaft construction at TCR. The western tunnel drive, between Royal Oak and Farringdon is one of five drives and will be the point at which the existing Network Rail services on the western section of the route enter the tunnels under central London.
Hanson establishes precast facility for tunnel segments
The tunnels are being lined with precast concrete fibre reinforced concrete segments manufactured in a tunnel segment manufacturing facility at Old Oak Common. The purpose built facility has an on-site QSRMC accredited, computer controlled concrete batch plant. The purpose built factory employs about 60 people and began producing segments in February 2012. The factory produces up to 200 segments per day and includes a laboratory to test the quality of the concrete to ensure that the segments have a 120 year life. The factory has been built specifically for the production of Crossrail’s tunnel segments on a site that will become home to a major Crossrail train depot once segment production is completed. BFK will manufacture more than 75,000 tunnel segments at the Old Oak Common site.
The concrete segments are transported by tunnel locomotives into the tunnels and loaded onto the 1,000 tonne mobile underground tunnel factory (the TBM). As the 140 metre long TBM advances forward, the precast concrete segments are built into 23 tonne rings to line the tunnels behind the TBM cutter head.
- Establishment of precast facility to produce segments for Crossrail C300 Western Running tunnels
- On-site QSRMC accredited computer controlled concrete batch plant with fully automated steel and polypropylene fibre dispenser equipment
- Heater systems and enclosed aggregate storage to achieve specified concrete temperature
- Planetary type mixer for speed to achieve total homogeneity and mixing of product
- Full traceability of all batch weights to include fibres, admixtures, powders and aggregates
- Integrated Hydronix system to record m/c of raw materials and concrete
- Dedicated trucks for concrete supply into segment moulds
- Specialist concrete mix design to achieve both tensile and compressive strengths
- Volume 80,000m3
- Traceability – each segment is specifically coded enabling each segment of each ring to be traced as to its location in the tunnel lining and that code can be referred back to an individual batch of concrete.