O’Keefe stabilises Tilbury2
By Leila Steed31 January 2020
Specialist contractor O’Keefe Group is nearing the completion of stabilisation works on the site of a decommissioned coal-fired power station near London, United Kingdom (UK).
Once home to the Tilbury Power Station and now known as Tilbury2, the site is being redeveloped as a container storage facility for the Port of Tilbury. At a cost of £200 million (US$262 million), the port terminal will become the UK’s biggest construction processing hub and the largest unaccompanied freight ferry port.
O’Keefe said it had almost finished preparing the brownfield site’s ground conditions, ready for main contractor Graham to carry the project’s construction phase.
Using the cement stabilisation technique, O’Keefe used two Wirtgen soil stabiliser machines to mix cement powder into the soil in-situ, the curing of which caused it to stiffen and increased its bearing strength.
The company then levelled and compact the 250,000 sq m (2.7 million sq ft) brownfield site to a 30% CBR (California Bering Ratio) value, to allow a layer of quarried type-1 aggregate to be laid as a base for the final reinforced concrete paving slab.
The works also saw O’Keefe use underground concrete foundations left over from the demolished power station.
Brian Doogue, contracts manager at O’Keefe, said: “The main advantage of soil stabilisation on this project is that it has allowed Graham to use site-won material and import less aggregate.”
The company used a fleet of 30 t tracked excavators fitted with breakers and pulverisers to dig out and break up the buried concrete, which was then turned into reusable aggregate by a Pegson crusher.
Brian added: “We are excavating all the obstructions and crushing them down for re-use as aggregate. That material is then used to back-fill drainage and service trenches.”
O’Keefe began the works in April 2019.