A generic trench shoring system, developed with the contractor, that supported more than 15 km of a 24 km bulk watermain across Auckland.
- Client
- March Cato for Watercare
- Services
- Temporary works design · trench shoring
- Location
- Manukau to Epsom, Auckland
- Scale
- 24 km · 1500–2000 mm pipe · 5 m deep
- Status
- Complete 2012
01 / Project overview
The brief
The Hunua 4 Watermain is a bulk water pipeline of approximately 24 km, 1500–2000 mm in diameter and buried about 5 m deep, running from Manukau to Epsom. One of the largest water pipeline projects undertaken in New Zealand, it supports population growth and improves the security of Auckland's water supply network.
We provided temporary works design for the trench shoring. The route passes along arterial roads and urban streets and through residential and commercial areas, and the ground changes constantly along it: from soft peat to volcanic tuff and basalt rock.
02 / Our approach
How we delivered it
One system, many ground types
Designing bespoke shoring for every length of trench would have been slow and hard to manage on site. Instead we developed a generic shoring system covering the full range of ground conditions on the route, from soft peat to volcanic rock.
Construction footage courtesy of March Cato
Developed with the contractor
The system was developed in consultation with the contractor, so the design fitted the way the crews would install it.
Proven over 15 km
The generic system has been used for more than 15 km of the watermain installation, giving the project a consistent, repeatable approach to trench safety along most of its length.
03 / The outcome
“A single, adaptable shoring system supported more than 15 km of trench on one of New Zealand’s largest water pipelines, through ground ranging from soft peat to basalt.”
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