Crossrail, London  

Transforming London

Dragados Sisk Joint Venture (DSJV) was responsible for the construction of 23km twin bore tunnels running from Victoria Dock in the east to the new Crossrail Farrington station in Central London. With a leg of tunnels splitting off between Stepney Green to Pudding Mill Lane.

Other works included establishing a PCC segment factory in Chatham produced 113,000 tunnel segments that were shipped from Chatham Dock to Limmo Wharf. 

This also included the design and construction of a new 200m-long marine berthing facility at Instone Wharf, located on the River Lea where it enters the River Thames, to be capable of handling approximately two 85m-long vessels. The facility was used for exporting approx. 1 million m³ of excavated tunnel material by self-propelled vessels. 

Challenges

Crossrail's largest tunnelling scheme was awarded to the joint venture company (DSJV) formed between John Sisk & Son and Dragados, a partnership which combined our expertise to deliver design and programme benefits for both client and future passengers alike. 

Known as “C305”, the project contract required the construction of 11.9km of twin bore tunnels. Known as the Eastern Running Tunnels, from London’s Limmo Peninsula to Farringdon and Victoria Dock, and from Stepney Green to Pudding Mill Lane. 

The contract included bored tunnels, sprayed concrete lined (SCL) tunnels, diaphragm wall shafts, segment manufacturing facility, spoil handling conveyor systems, and a 200m long berth and ship-loading facility for soil removal by marine transportation.

Diaphragm walls shafts & sheet pile cofferdams

Extensive collaboration with DLR (Docklands Light Railway) personnel at all stages of our process, from initial concept and methods of working onwards, was successfully implemented, allowing the construction of the diaghram wall shafts and steel sheetpiled cofferdam adjacent to the DLR.

A cofferdam is an enclosure built within, or in pairs across, a body of water to allow the enclosed area to be pumped out. This pumping creates a dry work environment for the work to be carried out.

Berthing facility

Construction of the berthing facility was completed using steel tubular piles and included 18m-long OD610x10mm crane beam bearing piles, 22.5m-long OD1220x25mm cantilever fender piles, and a section of cantilever sheet pile retaining wall using 40 number 15m-long AZ36 piles (380m²). 

Sheetpile walls are retaining walls constructed to retain earth, water or any other filling materials. Deadman anchor walls are thinner in section compared to masonry walls.

Technology

Crossrail’s eight tunnelling machines were manufactured by Herrenknecht in Germany and shipped to the UK in parts for re-assembly before use. Six of these were earth pressure balance tunnelling machines for digging through London clay, sand and gravel, while the remaining two were mix shield slurry machines for tunnelling through the wet chalk and flint beneath the River Thames.