The C300 contract involved the construction of two 6.8km dual running tunnels, from Royal Oak Portal through to Farringdon station. The tunnels were driven by two purpose-built Tunnel Boring Machines (TBMs) and are lined with pre-cast concrete segments, manufactured at a purpose built factory at Old Oak Common. The C300 tunnels are the second longest drives on the wider Crossrail project. The C410 contract involves the construction of platform tunnels and associated passages at both Bond Street Station and Tottenham Court Road, using sprayed concrete lining.
The project involved tunnelling in central London, comprising a densely populated area of residential, commercial, administrative and heritage buildings. We tunnelled beneath high profile areas including Hyde Park, Mayfair, the West End and Hatton Gardens. We also tunnelled beneath 172 listed buildings; including Grade I listed Paddington Station and St Barnabas in Soho, as well as various utilities and a total of 20 London Underground railway lines, with all assets remaining fully operational.
At peak production, over 50,000 tonnes of material from the TBMs was generated every week, which was transported to Wallasea Island, where it was used to create a wildlife habitat along the Essex coast.
The project achieved a CEEQUAL Excellent Whole Project Award, with a score of 90.1%. The success of the project was based on a strong commitment to sustainability that was embedded at the outset of the project. The project was developed in close consultation with stakeholders and local communities, which continued throughout design and construction. Key design and construction features of the project include:
- More than 99.99% of waste was diverted from landfill, with excavated material from the tunnelling work being reused in the development of a nature reserve at Wallasea Island
- A 2000 tonne reduction in CO2 emissions from vehicles achieved by using trains to haul tunnelling waste to the port at Northfleet, where material was then conveyed by boat to Wallasea Island
- Temporary and permanent works sourced from BES6001 certified suppliers
- The temporary railway used during the construction process was specially designed with resilient track supports to minimise airborne noise and reduce the transmission of vibration