Tunnels are being drilled deeper than ever before, with new challenges that require expert geotechnical consideration for a safe and successful outcome.

The geological conditions are a major factor when considering the feasibility of a tunnelling project, as they play a major role in the stability of the structure, recommended tunnelling depth and method.

Andy O’Sullivan has a reputation for delivering real value and managing underground risk very efficiently in the New Zealand tunnelling market. Using advanced design tools such as Plaxis 3D and fully-coupled flow analysis allows us to much more accurately assess soil and structure interactions and predicted ground displacements when compared to more traditional design methods. This level of expertise gives Clients confidence in our optimised solutions.

recent tunnelling projects we have worked on are

  • Auckland Central Interceptor – Geotechnical Peer Reviewers for the Ghella Abergeldie JV. We are also delivering designs on complex additional structures including the Central Confluence Chamber at the Mangere Treatment Plant.
  • Auckland City Rail Link – Design and construction supervision of 2.5m diameter mined adit through highly-fractured strong basalt (UCS>150MPa) 1.5m beneath one of Auckland’s main water supply pipes for the Link Alliance.
  • St Marys Bay to Masefield Beach Water Quality Improvement, Auckland – Design of temporary shafts and technical support to main contractor McConnell Dowell.
  • Ara Tūhono – Pūhoi To Warkworth, Auckland – Design of 3m diameter pipejack underneath live State Highway with very low overburden (<4m) for McConnell Dowell.
  • Barber Grove to Seaview Wastewater Treatment Plant Pipe Duplication, Lower Hutt – Design of all launch and retrieval shafts for project including tunnelling and geotechnical design support to main contractor McConnell Dowell.
  • Clinker Place to Manawa Wetland Stormwater Pipeline, Auckland – Design of all launch and retrieval shafts for project as well as ground retention support design, tunnelling, and geotechnical design support to main contractor Abergeldie Complex Infrastructure Ltd.

key personnel

Tunnelling Andy OSullivan

related projects