The 拢200m Tilbury2 port terminal, which is next to the existing 930-acre site in Thurrock, is set to become the UK's largest unaccompanied freight ferry port and the country's biggest construction processing hub.
O鈥橩eefe is nearing completion of groundworks on the part of the site on the north bank of the River Thames at Tilbury that was previously part of a coal-fired power station, demolished in 2017. O鈥橩eefe started work on the site in April 2019 and hands it over to Graham in February.
Principal contractor Graham is transforming this part of the development into a storage facility for containers at the Tilbury2鈥檚 roll-on/roll-off container terminal.
The 250,000m2 brownfield site has been levelled and compacted to a 30% CBR (California bearing ratio) value before a layer of quarried type-1 aggregate can be laid as a base for the final reinforced concrete paving slab.
The task has been made complicated by the presence of numerous underground structures, namely concrete foundations that supported the now-demolished buildings.
O鈥橩eefe had to excavate all the obstructions and crush them down for re-use as aggregate to back-fill drainage and service trenches.
The main technique employed was cement stabilisation, mixing cement powder with the soil in-situ. Once incorporated and evenly mixed into the soil, the cement cures, effectively stiffening the soil and increasing its bearing strength.
O鈥橩eefe used a pair of Wirtgen soil stabilisers to mill the soil while mixing the cement into it, followed by a Cat D6 dozer to level and compact the ground.
A fleet of 30-tonne tracked excavators, fitted with breakers and pulverisers dug out and broke up the buried concrete; a Pegson crusher processed it into re-usable aggregate.
鈥淭he main advantage of soil stabilisation on this project is that it has allowed Graham to use site-won material and import less aggregate,鈥� said O鈥橩eefe鈥檚 contracts manager Brian Doogue.
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