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

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

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

Andy O’Sullivan have provided Abergeldie innovative temporary works designs and geotechnical assessments reducing cost and programme on many of our construction projects.

Andy O’Sullivan are easy to work with and quick to respond to our requests.

Alastair Blackler - General Manager, Abergeldie Complex Infrastructure

Andy O Sullivan had a great understanding of the contractors focus to provide a safe and efficient solution for the shaft works on the Saint Marys Bay Project. Their willingness to investigate change and be flexible during the construction phase allowed the project to realise opportunities and achieve a successful outcome.

Grant McLean - Senior Site Executive, McConnell Dowell

We have worked with Andy and his team through the past two earthwork seasons on a number of challenges that have been encountered within our project. From stabilisation of large cut slopes in challenging ground. The solutions have been realistic, reasonable and constructable and a real ‘value add’ has been having some of our team regularly working out of Andy’s offices in true collaboration.