Stepney Green Case Study
BulkX axes 12 weeks from dig program at Europe’s biggest construction project.
Dragados Sisk Joint Venture
Stepney Green was one of the largest drive shaft sites for the Tunnel Boring Machines (TBMs) on the Crossrail project. Crossrail, back in 2013, was the largest infrastructure project in Europe.
At Stepney Green, the first step was to create two massive spray-lined concrete caverns for maintenance and services on Crossrail, these were going to be 50 metres long, 17 metres wide and 15 metres high. The caverns form the meeting point between the ‘Drive Y’ and ‘Drive Z’ TBMs, from Pudding Mill Lane and Canary Wharf, through Stepney Green, then on to Farringdon Station.
Due to this being a major drive site for the TBMs, a huge amount of spoil and waste material needed to be removed from the shafts. The excavation started using traditional methods, predominantly crane lift Boat Skips which were low capacity and presented a safety hazard when discharging into the muck bays, as the banksmen and operatives had to get near the skip while discharging.
As the skips were relatively low capacity, the excavators that were used to load the skips were left idle for long periods of time. The process of loading, lifting and returning the Boat Skips also took a long time, to the point that it seemed that the dig program would fall behind schedule.
Our solution: BulkX. BulkX was designed and developed at another site location of Crossrail and massively improved the efficiency on this project.
The system we proposed to site was a Direct-to-Muck Bay Discharge BulkX, essentially a large skip that had a capacity of 10,000 litres. The BulkX skip could discharge into the muck bay in 5 seconds, approximately 20X faster than a Boat Skip. It also improved safety on site due to no workers having to be in the discharge zone.
BulkX cut 12 weeks off the excavation program at Stepney Green. It allowed 24/7 excavation, better planning and reduced the amount of vehicle movements on site. As excavation was nearing completion, BulkX had removed in excess of 90,000m3 of London clay, equating to approximately 135,000 tons.
"It was a pleasure to have Conquip on site, the communication was first class and the solution provided (BulkX) really turned this project around."
Glenn Carr, Site Manager