Issue 105 - June 2023


Project: Slope Stability Guidance Documentation

NZGS Leader Richard Justice


The New Zealand Geotechnical Society have funding agreements with Toka Tú Ake EQC and MBIE for the development of Unit 1 of the proposed slope stability guidance series. This will be an overview unit, with a similar intent to Module 1 of the Earthquake Engineering Series, and is intended to be a ‘guidance’ document, outlining what competent practice should consider and assess. 

The structure of the development team comprises a Steering Group, mostly comprising current members of the NZGS committee and a Working Group, who are tasked with development of the content of the Unit. Progress to date includes:

  • Full steering group meetings have been held five times since December 2022, and continue monthly. A combined working group and steering group meeting was in held in May 2023.
  • Working group meetings are being held every few weeks as needed. A Report Author Breakdown has been shared for each part of the 12-section guidance document. Each section has a lead author and generally two further authors from the working group.
  • Most of the content of the sections of the guidance has been developed and is in the process of being standardised for language and conciseness.
  • The first Stakeholders update report was provided on 1 March 2023 to EQC, MBIE and NZGS.
  • Peer reviewers have been identified and are in the early stages of their review process.
  • The Development team expects to have Unit 1 in a form suitable for comment from NZGS Members in September this year

Project: Soil and Rock Description Guidelines

NZGS Leader Ross Roberts


First published in 1988, and revised 17 years later in 2005, the NZGS guidelines are 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 has been undertaken.

Feedback was collated in 2021 through online surveys and in the NZGS Symposium through a workshop, and this feedback has formed the basis of the committee’s work. The committee comprises Ross Roberts, Vicki Moos, Nathan Schumacher, James Elvy, Darren Maxwell, Susan Tilsley, Stuart Read, Ann Williams, Geoff Farquhar, Rob Damhuis and is project managed by Amanda Blakey.

Progress and meetings have been hampered by the adverse weather events in New Zealand in January and February 2023 as group members have been involved in significant assessment and work in a number of affected regions. The committee is now getting back up to speed and has held two meetings in April and May. This follows eight meetings in 2022.

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 as well as making improvements throughout to resolve the issues raised by members, while aiming to maintain alignment with best international practice wherever possible.

The committee is aiming to deliver a draft for consultation in late 2023.

Project: NZ Earthworks specification NZS4431 – NZ Ground Investigation Specification

NZGS Leader Ross Roberts


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.

This project was put on hold as group members responded to the adverse weather events in New Zealand in January and February 2023. The work is expected to re-start in the near future and an update will be issued once this has commenced.

Project: Occupational Regulation Update

NZGS Leader Jen Smith


NZGS is engaging with ENZ in their work with MBIE on occupational regulation. At present things are going through cabinet process prior to a government committee being formed, but we are keeping up to date on any changes in the proposed policy, and the expected timeframes of the rollout of occupational regulations and the potential impact to our NZGS members. The next update is expected before November 2023, with more tangible knowledge and information for our members is likely to be available towards mid 2024.

Project: NZGS Climate Change Focus Group

NZGS Leader Martin Larisch


The newly established working group has met each month over the past two months to discuss and define the proposed aims of the group, the target focus areas and the mission statement and those items will be finalized during the next meeting in June 2023. 

The organisation of the 2nd NZGS Climate Change Symposium for late 2023 (first half of November 2023) has been discussed and further work will be carried out in the next few weeks.

The NZGS Climate Change Focus Group is currently looking to collaborate with The Ground Level Alliance (Australia) to explore common goals, aims and research opportunities. The Ground Level Alliance is an Australian group of Civil Construction Professionals which aims to empower and equip construction professionals to make sustainability a daily practice.

Project: Ground Anchor Guidance Document

NZGS Leader Sam Glue


The ground anchor guideline has been issued as a draft for comment, this was prepared over the last 2 years by a team of NZGS volunteer subject matter experts, the NZGS management committee would like to thank the team for their hard work and dedication in preparing this guideline. This document is intended to be used by geo/structural professionals involved in the design and construction of ground anchors and assist parties to comply with their obligations under the Building Act. The guideline has been developed using recognized international design standards, but has been specifically prepared to follow New Zealand best practice. The document is released as a draft for comment and we encourage our members to use the document over the next 6 months and provide feedback to the development team for any improvements or clarifications required. Please provide all comments by email to

NZGS will be holding a series of presentations at local branches across the country to outline what is in the guideline and how to use it for future projects. A detailed NZGS training course will also be prepared and training sessions will be run around the country. The itinerary for the presentations and training courses will be released in the near future.

Project: NZGS Short Courses

NZGS Leader Emilia Stocks


In March, NZGS ran a series of courses across Auckland, Wellington and Christchurch on Soil slope stability analysis by Prof. D.V Griffiths and one day course in Wellington on GIS for Geotechnical Professionals by Colin Mazengarb. Both courses have been well received. Further GIS for intermediate and advanced users is expected to run across NZ this year. 

Issue 105 - June 2023, NZ Geomechanics News
Issue 105 - June 2023, NZ Geomechanics News
Project News / Case Study

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