Sapphire to Woolgoolga (N224)

Project status: 
Industry sector: 
Bored Piling
Track Mounted
Our Client: 
Leighton Fulton Hogan Joint Venture
End Client: 
Roads and Maritime Services NSW
Project Time Frame: 
2010 to 2012
Pacific Highway between Sapphire and Woolgoolga
Sapphire to Woolgoolga N224  Sapphire to Woolgoolga N224  Sapphire to Woolgoolga N224

Key Challenges

  • Adapting drill techniques and methodologies to accommodate a variety of ground conditions across the piling locations including high strength rock at ground level, underground springs, 36 m deep piles socketed into moderately weathered rock
  • Drilling under bentonite and drilling through gravel bridging layers requiring permanent casings
  • Adapting to Head Contractors program deadlines requiring numerous staged moves to bridge sites spread across a distance of approximately 20km
  • Implementing high level of controls working adjacent to live power lines and adjacent to live traffic on the Pacific Highway


  • Installation of 320 bored piles ranging from 600 mm dia to 1800 mm dia for 21 bridges
  • Drill depths up to 37m
  • Combination of Segmental Casing, Temporary and Permanent Liners and bentonite used for soft ground support
  • Schedule of rates contract

Geotechnical conditions

  • Soft alluvial clays with sand layers over moderately weak to medium strength rock. Rock at 5 m to 50 m. Some piles were constructed under bentonite up to 50 m depth.

Key Plant

  • 1 x BG28  with conventional drilling tools, segmental casings, bentonite equipment and desander, tremie tubes and 80t service cranes.