Slip A4 – enabling works were completed during the holiday period with 102 piles installed in just 6 days!

SH1 Mangamuka Gorge slip repairs – January update

Kia ora koutou,

Welcome to the new year. We hope you all had a fantastic holiday period.

Even with many of the team taking a well-deserved break, work continued on site with one team who made significant progress over the break, drilling and pouring an impressive 102 smaller piles in just 6 days! 

The teams onsite are making the most of the drier weather and are continuing to undertake night works to ensure that we maintain this progress.

With more sunshine than we have seen in a while, we have put extra precautions in place for any work that may increase the risk of fire. We are also making sure that our workers remain safe in the sun.

We’ve got a very busy year ahead of us, and we will continue to keep you updated. Thank you for your continued understanding, patience, and support.

Progress Update

We are now mobilised on 13 of the 15 critical slip sites.

Slips A1 and A2

All enabling works and permanent casings for the 1050mm diameter piles are complete.

The programme for the permanent piling operations at this slip is one of the final tasks among all the critical slips.

Since we have positioned the large rigs further up the site, this will be the last slip site to be completed as we exit the site with the big rigs and cranes.

Slip A3 – preparation for the capping beam to be installed.

Slip A3

Despite challenging ground conditions, the team has successfully installed a total of 28 out of the 42 planned permanent piles, with the capping beam started at the southern end.

Slip A4 – enabling works were completed over the holiday period. Here you can see the capping beam being installed.

Slip A4

Enabling works are complete, including clearing shrub and excavation, work platforms, piling, and capping beam.

102 temporary piles and capping beam were drilled and poured over the holiday break to minimise disruption to the rest of the site.

Slip A5 – capping beam and work platforms are in place.

Slip A5

Having successfully completed the piling, capping beam and work platforms before the break, our team is now on-site and geared up for the next phase.

We are now installing the anchors, which play a crucial role in providing stability and support to the piling system installed. Anchors in piling are designed to prevent lateral movement and ensure the structural integrity of foundations. They are typically installed deep into the ground to secure the piles and distribute loads evenly.

Slip A6 – enabling works are complete and permanent works are underway. Here you can see the temporary piles and the layout for the permanent pile casings.

Slip A6

Enabling works are complete which included no-longer required work platforms, and the installation of stormwater manholes and rock spall walls.

Permanent works are now starting.

Slips A7 and A8

The design has been finalised and the team is programming the construction around the other work on site.

Slip A9 – reinforcing cages that were lowered into the pile hole and filled with concrete. There may be 2 or 3 of these spliced together in a single pile.

Slip A9

The permanent works are continuing with casings being welded and secured.

A constant and consistent supply of concrete has resulted in the completion of 23 of the scheduled 53 permanent piles.

This slip has had its challenges, with the drill rig unexpectedly reaching its operating limit due to the depth of the piles, but work remains on track.

Slip A26 – coring has been done in preparation for the piles. However, work has been temporarily paused to allow access to other operational sites.

Slip A26

Enabling works are complete.

Works around this site are continuing, but the main permanent works have been temporarily paused to allow access for other slip sites that are more established. Work is programmed to recommence once slip A27 is complete.

Slip A10 – test anchors being installed.

Slip A10

Test anchors have been installed and tested, and they are now being included in the design to anchor back the existing gabion wall.

Slip A11

Enabling works have begun on the road corridor, including traffic diversions and the construction of barriers around the work area.

The design has been completed, and the team is continuing to work with DoC and hapū to finalise the approvals and management of the retreat on this slip site.

Approximately 24,000m3 of material needs to be removed, and the existing road needs to be realigned away from this slip-prone site.

This is a complex slip site with considerable challenges and environmental controls around wildlife and habitat management.

Slip A12 – installed section of capping beam. The holes are where the ground anchors will be installed.

Slip A12

Piling has been completed, with 39 permanent piles and lagging plates now installed, and the capping beam is two-thirds poured.

Slip A13 – permanent piles and casings being installed.

Slip A13

The team is continuing to make progress with the installation of the 1050mm diameter permanent piles, with 19 out of 41 piles now poured and a further 33 casings installed.

Slip A27 (right) – platforms, Universal Column (UC) beam and precast wall installation. Work has to be carefully coordinated around the A12 and A13 slip repairs.

Slip A27

Progress is good with 15 out of the scheduled 32 Universal Column (UC) piles and precast walls being installed.

Worker of the Month

Introducing Rachel Taitimu, our Mangamuka Gorge 'Worker of the Month'.

Rachel is a Project Engineer with the CLL Northland team. With extensive experience in large-scale piling projects spanning across the country, Rachel's dedication and expertise make her a critical part for the Quality Assurance of the work undertaken on site.

Rachel embarked on her career in civil engineering as a single parent of 3, juggling the demands of graveyard shifts as a prison officer while pursuing a degree in Environmental Engineering. During her studies, Rachel welcomed another addition to her family, managing her academic pursuits while nurturing her new-born and even taking her baby to classes.

Upon the successful completion of her degree, Rachel made history as the first Māori wāhine to graduate as a Civil Engineer. Her journey is a testament to resilience, determination, and breaking new ground in her chosen profession.

Need more information for your local community group?

Our latest flyer ensures you and your community are kept up to date.

If you would like some printed copies to hand out to your whānau or community group, send us an email at northlandproject@nzta.govt.nz with your name, mailing address and the number of copies you need. We’ll then pop them in the post directly to you.

To view the electronic version of the flyer, click here.

For more information on the project, please click here for the website.

More information

For more information on the SH1 Mangamuka Gorge slip repairs, contact us at northlandproject@nzta.govt.nz

Visit our website www.nzta.govt.nz/mangamuka