Work on the westbound cavern is also well underway.
According to Crossrail project managers, the Stepney Green caverns are one of the largest mined caverns ever constructed in Europe using a spray concrete lining. The eastbound cavern is where Crossrail trains will branch towards Stratford or Woolwich and so is scaled to accommodate the two tunnel boring machines (TBMs) – Victoria and Elizabeth – that are due to arrive later this year on their way to Farringdon via Canary Wharf, Whitechapel and Liverpool Street stations.
The cavern is 50m long, 13.4m wide and 16.6m high at its widest point. To construct the cavern, the team had to excavate 7500m3 of material and apply 2500m3 shotcrete to the walls.
Due to the site’s urban location, alongside a school and a technical college, a concrete batching plant was built on site to manufacture the concrete for the cavern. The team also used a special cutting tool to remove temporary supports, rather than the traditional noisier method of using an impact hammer.
Sprayed concrete lining (SCL) construction manager Rob Gordon said: “Getting to this stage in our programme in just over three months is an incredible achievement, especially given the site constraints.”
Throughout the works, the team has ensured close monitoring and control of concrete strength and ground movements.
Project manager Peter Main added: “Thanks to thorough planning and collaboration by our sprayed concrete linings team, our contractor Dragados Sisk JV and Crossrail, we remain well on schedule for the arrival of the TBMs later this year.”