CORUS HYDROBARRIER has completed the design, supply and installation of a sealed sheet pile retaining wall for an underground storage tank next to the River Exe in south west England.
Main contractor Dean & Dyball built the 35.5m by 15m tank, which forms part of the upgrading and development of Exeter's water system by South West Water.
The piling, designed by Corus Hydrobarrier (part of steel manufacturer and supplier Corus International), supports a retained height of 6m. Before delivery, pairs of LX32 piles were welded together, painted and the interlocks sealed using a system developed by Corus at its research development & technology centre.
Foundation contractor Steel Foundations used a combination of a vibration hammer and a heavy duty hydraulic hammer to drive the sheet piles through dense gravels and into the underlying mudstone to a depth of up to 8m.The 870m 2of piles were driven in only 10 days, saving three weeks off the programme.
The first real test came shortly after the tank was finished, when exceptional flooding hit the area.Despite a 6m head of water, and the tank being open, it remained watertight.