tunnelling

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

related projects

Auckland Central Interceptor

NZ’s largest water sector tunnelling project

St Marys Bay to Masefield Beach Water Quality Improvement

challenging urban tunnelling project

Design and detailing of the soil – structure interaction for the Main Wharf North project was a considerable challenge for all involved. The ground improvement was required to stabilise the existing fill and alluvial soils, provide the majority of the lateral restraint for the entire wharf and back span slab in a highly seismic zone, all without excessive restraint of thermal and shrinkage actions. Andy and his team provided strong leadership in this complex interface, relentlessly driving efficiency and value in the solution.

Daniel Patten - Engineering Manager, McConnell Dowell

The Andy O’Sullivan team developed the design for the temporary works as part of the Barber Grove ECI. This included several aspects of geotechnical design from retaining structures to specialist considerations associated with TBM works. The AOS team provided practical and progressive solutions in a demanding geotechnical environment and as a result, the well-considered designs bought real value to the project.

Daniel Crichton - Senior Principal Engineer, Downer Group

March Cato have enjoyed working with Andy O’Sullivan. We feel confident that we can pick up the phone at any time and get talking to a team who properly listen and take the time to understand the challenges we’re facing, so they can develop up a site specific, sensible and constructable solution to keep our jobs moving along safely.

Tony Mills - General Manager, March Cato

Andy used cutting-edge software to design an ‘underground pipe bridge’ through a major landslide. To our knowledge, this solution has never been constructed before and saved over two years of project delays and millions of dollars.

Andy Corbett - Commercial Director, Pipeline & Civil Ltd

We have worked with Andy and his team for a number of years now and we keep coming back to them as their approach to geotechnical design is always practical and efficient. They do not shy away from challenging designs and will always go that extra mile to make sure their designs are constructable.