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Bachy Soletanche installed 12 ground anchors through the existing dock wall to cater for additional forces which would arise during excavation.

A tough rock to crack at Rosyth Dock

October 28, 2009

Bachy Soletanche extends piles through dolerite rock with innovative dowel technique. The tender winning design recently sent Bachy Soletanche to the large scale Rosyth Dock expansion project to install a piled retaining wall as part of the entrance extension.

• The retained piled wall is part of works to widen the current entrance by 4m
  

  

• It was the innovative solution using dowels to extend the piles into Dolerite rock which won Bachy Soletanche the project
• It was a more efficient and cost effective alternative to piling several metres deeper for the same effect
• Installed 50m (linear) of secant pile wall to a 25m depth with 3m dowel extensions
• Wall required 50 piles with 1.3m diameters, installed using the large diameter rotary bore (LDA) technique
• These piles were installed behind the existing entrance wall
• The permanent cage incorporated a tube in the centre of the pile wide enough to insert a 300mm diameter dowel. These cages were especially designed for the project (Pictured)
• A string of drill rods was placed down the tube and a rock socket was formed with a ‘down the hole hammer’
• A 6m long dowel was then grouted into the pile and the rock
• The piles were heavily reinforced to endure massive forces with the full pile length cages weighing up to 14tonnes
• Also installed 12 ground anchors through the existing dock wall to cater for additional forces which would arise during excavation (pictured)
• Excavation work between the temporary piled wall and existing dock wall is taking place until December 2009
• Bachy Soletanche conducted the twelve week contract from Easter to mid July 2009 and was sub-contracted by main contractor Bam Nuttall