Piling Specification Review

NZGS management committee lead: Tony Fairclough

Core team: Andy Dodds (lead author), Tessa Beetham, Paul Berriman, Ryan Clarke, Lian Ching Oh, James Harrison, Gil Johnson, Andrew Langbein, Martin Larisch, Malcolm McWhannell, Rob Presland, Nicola Ridgley, Michael Robinson, Nick Wharmby


In 2019 a Panel of Experts was jointly appointed by the SESOC and NZGS National Management Committees to review and update the Auckland Structural Group (ASG) “Piling Specification” document. The last version of such document (Rev G) was issued on 12 March 2002.

The Project Panel of Experts has issued “Revision 1 – Final Draft for Public Comment” version of the SESOC/NZGS Piling Specification for feedback. Please return your completed feedback form via email to Teresa Roetman and Tony Fairclough by 6:00pm on Wednesday 28 April 2021.

Further details and links to download the consultation documents are available on the NZGS website here: https://www.nzgs.org/sesoc-nzgs-piling-specification-consultation-and-feedback/

NZ Ground Investigation Specification update

NZGS management committee lead: Ross Roberts

Core team: TBC

Programme: This project commenced in mid 2022 and is nearly ready for feedback from members. The focus of the work has been on improving the geophysics section.

The original specification was published in 2017 for feedback. The document is now ready for an update based on this feedback. The main proposed changes are simplification of references, improving the geophysics section, and creation of a simplified schedule table for small projects.

Soil and Rock Description update

Project lead: Ross Roberts

NZGS management committee lead: Ross Roberts

Core team: Stuart ReadSusan TilsleySteve CookeDarren MaxwellVicki MoonGeoff FarquharAnn Williams, James Elvy, Nathan Schumacher

Programme: Draft complete late 2023 for consultation

The NZGS has formally launched a project to review the Field Description of Soil and Rock. First published in 1988, and revised 17 years later in 2005, it is generally considered to be a great document. Feedback has suggested that some improvements could be made, and given that this guide is now approaching its 16th year a review is warranted.

The team has identified that the updated document should focus on field description (not classification), and is developing a more clear and consistent order-of-terms to enable more efficient data entry.

Ground anchor specification

Project lead: Katy Cottingham

NZGS management committee lead:

Core team: Brabha PathmanathanGreg SaulStuart FinlanKevin AndersonKyle WebsterDavid SharpIan McPhersonJethro NeesonNima TagipouranRobert HillierKiran SaligameTony KaoTim PervanTim FarrantLars Schmidt


The NZGS has identified that there is an absence of practical guidance suited to the market for the design and construction of ground anchors. The development of a guideline to establish the baseline of good practice will be beneficial to the broader community.

Slope stability guidelines

NZGS management committee leads: Richard Justice

Steering Group Members: Richard Justice, Eleni Gkeli, David Stewart, Ross Roberts, John Scott

Programme: Steering and Working groups meetings to be held throughout 2023 with the project aim of a deliverable report (Slope Stability Unit 1) to be published in February 2024

The New Zealand Geotechnical Society has produced six Earthquake Geotechnical Engineering Guideline Modules covering a range of geotechnical topics. These did not specifically address slope stability. 

In 2019 the NZGS management committee agreed to consider the creation of a seventh module for the assessment of slopes under seismic loading. It quickly became apparent that addressing the seismic case without first dealing with the static case would be problematic given the varied practice currently identified in the industry. 

Following a survey of NZGS members, concerns were identified that slope stability practice in New Zealand required more guidance.  The Slope Stability Unit 1 guidance project began in earnest in February 2023, after securing funding from EQC and MBIE, in collaboration with NZGS seed funding.  The Slope Stability Unit 1 project will progress through 2023 with the deliverable of the final report in February 2024.

A working group has been identified, and with oversight from the steering group (established in late 2022), initial meetings have been held.  Robust discussion around issues will ensure that a reliable document is produced and the group looks forward to updating members and Stakeholders regularly.

Young Professionals Training Modules

Project lead: Miles Boub

NZGS management committee lead: Helen Hendrickson

Core team:


A gap has been identified in the training available for recent graduates. A small group is developing a series of practical training materials to help bridge the gap between university learning and professional practice.

NZ Earthworks Specification

NZGS management committee lead: Ross Roberts

Core team:


During an update to NZS4431 it was identified that the lack of a consistent earthworks specification suitable for residential subdivision was causing issues with consistency and quality of work. This project aims to develop a specification compatible with the soon to be updated NZS4431.  A short form version will subsequently be developed for small, low risk earthworks projects.

Expansive soils practice note

NZGS management committee lead: Jen Smith

Core team:

Programme:  Hopefully starting Sept/Oct 2022

Concerns have been raised by geotechnical practitioners in New Zealand about our approach to identifying, classifying and mitigating the effects of expansive soils. This project is intended to provide guidance for practitioners and consenting authorities to reduce the risks posed by expansive soils.  This project is intended to link in with our work on the ongoing revision of NZS 3604:2011.

Building Act section 72 guidance

NZGS management committee lead: Sally Hargraves

Core team: Nick Rogers, John Scott, Jeff Farrell, John Westerson.

Programme:  Starting Sept 21 (hopefully complete 2022)

There is an inconsistent use and application of s72 of the Building Act across NZ.  Some guidance has been developed for some parts of the country, but the aim of this guidance will be to provide more clarity and consistency across New Zealand in terms of when Councils might implement s72 and under what circumstances.  This will hopefully be delivered as joint guidance with MBIE.

The guidance development team would hopefully comprise a mixture of geotechnical consultants; those with experience of the EQC Act 1991 and those with experience of implenting s72 at Territorial Authority level.  If you have an interest in this area, please contact the lead.

Subsoil drainage guidance

NZGS management committee lead: Sally Hargraves

Core team: currently in development

Programme:  t.b.c.

There is currently no NZ specific guidance on the design, construction and maintenance of subsoil drains.  This guidance would aim to provide guidance on good (not necessarily best) practice in this area for use on land development projects, especially where filling is proposed over gullies or soft, wet ground; or where springs / seepage may be present.

The guidance development team would hopefully comprise a mixture of geotechnical consultants and contractors representatives.  Please contact the lead if you have an iterest in this area and think you may be able to contribute.

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