Northern Line Extension to Battersea

London, UK

KB International supported Cementation Skanska’s drilling operations with the Enhanced SlurryPro CDP System on a $1-billion mass transit tunnel project in the heart of London. In addition to facilitating transportation and improving public spaces, the tube extension is expected to create up to 25,000 new jobs and 20,000 new homes in Vauxhall, Nine Elms, and Battersea. The Northern Line Extension, (NLE), designed and built by The Joint Venture Ferrovial Agroman Laing O’Rourke, will extend the Underground Northern Line, continue the Charing Cross Branch, and add two stations by 2020.

KB worked with Cementation Skanska to overcome a trifecta of challenges during the drilling of 74, 60-meter-long shafts ranging from 1.5 to 2.5 meters in diameter. The soils including alluvium, London Clay, and Lambeth Sand. At 2.5 meters in diameter and 60 meters in depth, these were the largest shafts ever drilled under a polymer system in London. One of the piles was held open for 7 days due to issues with the cage. During this time the pile experienced no fluid loss or collapse and was able to be concreted without being backfilled and re-drilled. Proximity to the River Thames required a heightened level of environmental sensitivity. The environmental profile of the Enhanced SlurryPro CDP System was the perfect match.

KB also worked closely with Cementation Skanska on both the system and plant design to maximize regeneration of the drilling fluids. Based on these efforts, the project come in under budget for the slurry and all shafts were successfully drilled.