Restricted Access Piles East Kent Access, Ramsgate | Keller UK

Restricted Access Piles East Kent Access, Ramsgate

The installation of 520No sectional flight augured bored piles to provide support and mitigate settlement during the construction of a new dual carriageway under an existing railway crossing at East Kent Access, Ramsgate. 

Sectional Flight Auger piling techniques were used to construct 450mm Ø bored piles within the 2no pilot tunnels.  Up to 4No specially modified electro-hydraulic piling rigs were used to carry out the works in 2.7m headroom.  The installation of the piles allowed the clients proposed construction method to be implemented, removing the need to suspend train movements along the busy Ramsgate to London mainline. 

  • The works required the installation of SFA bored piles using electric rigs to a depth of 14.0m BGL to provide support to the bridge deck sections as they were being jacked under the rail crossing using traditional tunnelling methods.
  • The ground conditions consisted of Grade 2-3 Chalk down to 8.0m BGL overlying  structureless Chalk (grade Dm).
  • The site compound was situated at the openings of the pilot tunnels where an automated batching system was erected supplying the grout for the piles.  Access to the tunnels was on either side allowing 4no rigs to be utilised.  To complete the project in the required 13weeks, 24hr working conditions were implemented and noise reduction measures were installed.
  • A total of 520No piles were installed (260 within each tunnel).   Up to 12 piles were being installed every 24hrs.  Crews of 4 men manned each rig allowing familiarity and team building.
  • Piles were installed at 1.0m c/c. Structured  sequencing was implemented to protect the newly installed piles from connecting with adjacent piles.
  • Restrictions on the drilling diameter through the pilot tunnel sections resulted in a 473mm Ø coring barrel being developed.  This  allowed the tunnel sections to be drilled and the 450mm Ø required piles to be installed.
  • Due to the tunnel height rigid tremie pipes had to be implemented and installed in 1.0m sections to allow safe grouting of the piles.

System : Restricted Access Minipiles

Client: Highways Agency

Contractor: Volker Fitzpatrick

Engineer: CH2M HILL

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