Solutions
Foundations, retention, bridge construction and ground improvement — purpose-built restricted-access equipment across the full spectrum of ground engineering.
New Zealand's ground engineering challenges are as varied as its geology. Soft alluvial soils beneath urban developments, variable fill on brownfield sites, liquefiable ground in earthquake-prone cities, steep terrain requiring piled foundations, and ageing bridge infrastructure demanding rehabilitation — these are the problems that GSI NZ's Ground Engineering division is built to solve.
Our Ground Engineering capability covers the full spectrum of foundation, retention and ground improvement techniques — from CFA piling and deep soil mixing to jet grouting, in-situ trench mixing, foamed concrete, bridge abutment repair and single-span bridge construction. What makes our approach distinctive is that all of this is delivered by a single integrated team of geotechnical engineers and specialist construction crews, operating purpose-built restricted-access equipment that can work in locations where standard plant cannot.
WHY GSI NZ
Step 1
Ground investigation defines soil conditions, bearing capacity, and structural requirements. Our engineers design the piling or wall solution, specifying diameter, depth, and installation parameters to meet the project's load and access constraints.
Step 2
The FD45 CFA rig or in-situ trench mixing equipment is mobilised to site. Installations are carried out with real-time monitoring of auger rotation, concrete volume, and penetration rate — in spaces where standard piling equipment cannot work.
Step 3
Integrity testing, load testing (where specified), and full as-built records confirm pile and wall performance. A completion report with all QA documentation is provided on handover.
Low-vibration continuous flight auger piling for foundations, retaining walls, and slope stabilisation. FD45 restricted-access rig, 450–600 mm diameter to 20 m depth.
Continuous stabilised trench walls 550–950 mm wide to 16 m depth, first deployed in New Zealand by GSI.
Rehabilitate failing bridge abutments without full deconstruction. Faster, cheaper and less disruptive than reconstruction.
Single-span bridge construction using GCS® abutment technology. Faster, lower cost and simpler to consent than conventional methods.
In-place repair and rehabilitation of failing retaining walls: MSE, gabion, pile, concrete and historic stone structures.
MSE, gabion, pile and historic rock wall repair without full reconstruction. SuperNails™ through-face reinforcement.
In-place bridge abutment rehabilitation — the existing structure stays, closures measured in days not weeks.
Complete single-span bridge replacement using GCS® technology — no deep foundations, no formed concrete.
EQUIPMENT
Our In-Situ Trench Mixing system — the first of its kind deployed in New Zealand — forms continuous stabilised trench walls 550–950 mm wide to 16 m depth without excavation or spoil removal. The technology is well established in Europe and North America for cut-off walls and groundwater barriers, and GSI NZ brought it to New Zealand to address applications that were previously impractical or uneconomic for the local market. Ground Engineering solutions are frequently combined with our Geohazard Engineering and Specialist Grouting divisions on the same project — giving clients a single integrated team across all ground-related challenges.
GSI NZ's ground engineering capability was significantly strengthened through the 2019 acquisition of Hiway Geotechnical, which brought CFA piling, jet grouting, in-situ mass stabilisation, and in-situ trench mixing under the GSI roof. That acquisition expanded our offering from geohazard response into comprehensive ground engineering across New Zealand — and today our Ground Engineering division operates alongside our Geohazard Engineering and Specialist Grouting divisions on the same project when the scope demands it. Every project is fully documented — QA records, as-built drawings, and testing results provided on completion.
GROUND ENGINEERING
CFA piling and GCS wall on a constrained coastal site in Napier.
View Project →SPECIALIST GROUTING
126 soil-cement columns to stabilise an active landslide mass — Central Hawke's Bay.
View Project →SPECIALIST GROUTING
Ground improvement and foundation works for major Christchurch aquatic facility.
View Project →Get in Touch
From urban piling to mass stabilisation, our in-house engineers design and build every solution. One contract, one team, no gaps.
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