Infrastructure & Land Development
Geotechnical insight for the ground beneath New Zealand’s growing infrastructure.
Ground Conditions, Understood From the Outset
Every infrastructure or land development project starts with the same question: what’s actually in the ground, and what will it take to build on it. Earthtech has been answering that question for New Zealand developers, councils, contractors, and homeowners since 1989, working across everything from single house sites to major roading corridors.
Our team understands current design codes and construction practicalities, because we’re regularly on site alongside the people doing the building. We work directly with contractors, planners, consultants, councils and government agencies, which means we understand what’s driving a project and can meet the geotechnical requirements from concept through to completion.
Being a smaller, specialist firm works in our favour here. We’re agile enough to respond to fast-moving projects, and our portfolio includes landmark developments that stand alongside anything the larger firms have delivered.
Applications & Services
Our team is involved at every stage of a project, from feasibility studies and site selection through to detailed design, remedial works, peer review and construction inspections. Senior engineers stay hands-on throughout, so you’re never handed off to someone unfamiliar with your project.
Design & Project Expertise
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Geotechnical design for roading projects, bridges, and major or minor culverts -
Small to large subdivisions, including canal, waterway and retirement village developments
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Identification of geohazards and assessment of adverse geological conditions
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Remedial works for slope instability affecting roads and infrastructure
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Category 1 geotechnical checking and independent peer review
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Expert evidence at council and Environmental Court hearings
Field Investigation Expertise
Every investigation is tailored to the site, from a handful of hand augers to multi-day programmes coordinating teams of specialist subcontractors. Our field capability includes:
Geological mapping of landforms, geomorphology and exposures
Hand auger bores, shear vane and scala penetrometer testing
Test pit investigations and in-situ permeability (soakage) testing
Cone Penetration Testing (CPT and sCPT) and machine-drilled boreholes, delivered with specialist subcontractors
Big Project Experience, Without the Big-Firm Overhead
The Earthtech team has worked across everything from residential house sites to regionally significant transport infrastructure, and that range is exactly the point. Our size means senior engineers stay involved on every project, not just the ones that make the news. It also means you’re dealing with the person who understands your site, not a rotating cast of account managers. Clients come back to us because the work holds up, and because we’re straightforward to deal with from first site visit to final sign-off.
“Earthtech is a long-standing go-to geotechnical subconsultant for BBO bridge projects. I have found Michelle to be consistently helpful, insightful, and responsive.”
Pang Chong Heng – Director / Structural Engineering Manager
Bloxam Burnett & Olliver Ltd
Our Infrastructure & Land Development Projects
Wairere Drive-Cobham Drive Intersection Grade Separation
Project Summary Earthtech carried out detailed geotechnical investigations for the four-lane bridge, associated on- and off-ramps, and road alignments. This included the design of deep soil mixing ground improvement to address liquefaction effects, retaining walls, earthworks, stability assessment adjacent to live roads and nearby gully, and dewatering for buried services construction. The scope of work included construction inspections and producer statement (PS4) signoffs. During the course of the project, we formed effective working relationships with the project team. Services Provided Detailed geotechnical investigations, including seismic testing. Geotechnical design of bridge foundations, retaining walls, ground improvement, slope stabilisation works, preloading to address ground settlement effects, dewatering and groundwater control works, and many more. Contractors' temporary works, including haul road formation. Specialist…
Ngaakooroa Stream Bridge Dewatering
Project Summary Elevated artesian groundwater pressures coupled with overhead power lines, created challenging conditions for bridge pile construction. Working with the project team, Earthtech provided a dewatering bore design solution to depressurise the artesian groundwater levels. Timeframes were very tight, meaning that the dewatering design, consenting and dewatering bore construction stages significantly overlapped. The project was delivered on time, and Earthtech assisted with real-time groundwater level control and monitoring during piling activities. Services Provided Groundwater analysis and design of a bore-field dewatering system. Preparation of the Assessment of Environmental Effects and consenting of the groundwater take (dewatering) and diversion activities. Ongoing involvement and contractor support during dewatering and piling activities, including assisting with the setup of groundwater level alert and…
Whitianga Waterways, Marden Cove Waterways and Pauanui Waterways Canal Subdivision Developments
Project Summary Earthtech has been assisting these clients with canal subdivision developments since the 1990s. Across these projects, we have supported the developer through the design and construction of multiple subdivision stages, including associated retirement villages, commercial buildings, and road access bridges. Services Provided Geotechnical investigations to define ground and groundwater conditions, including machine boreholes, CPT testing and hand augers. Geotechnical subdivision design, including the design of preloads to address consolidation ground settlement effects, ground improvement to manage liquefaction effects, slope and canal edge stability and stabilisation, and geohazard identification. Inspections, verification testing and general advice during construction. Preparation of Geotechnical Completion Reports and geotechnical producer statement sign-offs. Project Conclusion These projects stand as a testament to the long-standing care…
Collins Road Wastewater Facility Dewatering
Project Summary Earthtech became involved in the project when unexpected groundwater conditions and piping in the excavation floor were encountered during construction of 7.8m to 9.1m deep excavations and shafts for wastewater infrastructure construction. We carried out groundwater investigations and pump testing to define a dewatering solution that provided a dry, safe and stable excavation during the 6-month construction dewatering period. Earthtech's involvement continued during construction, with the management of pumping rates and monitoring to ensure that neighbouring properties and infrastructure were protected from dewatering effects. Services Provided Groundwater investigations and pump testing. Groundwater analysis and design of a bore-field dewatering system. Preparation of Assessment of Environmental Effects and consenting of the groundwater take (dewatering) and diversion activities. Preparation of…
Smales Road Commercial Development
Project Summary Earthtech carried out geotechnical investigations and design for four large commercial buildings. Ground conditions were challenging and variable, including compressible ground conditions with weak soils and undercuts through to hard volcanic soils and building across cut-fill lines. Warehouse floor areas ranged between 3,160m² and 6,570m², supporting floor live loads of between 40kPa and 50kPa. The development was designed to a high standard, achieving 140% of New Building Standard (NBS) requirements. Services Provided Geotechnical investigations to define ground and groundwater conditions, including machine boreholes, CPT testing and hand augers. Geotechnical design of commercial buildings and warehouses, including foundation design, ground settlement predictions, retaining walls, and bridging of buried services. Inspections, verification testing and general advice during construction. Production Conclusion…
Talk to Our Infrastructure and Land Development Team
If you’ve got a site to assess, a subdivision in the pipeline, or a project that needs Category 1 peer review, get in touch with Michelle directly. No call centre, no handoffs, just the specialist who’ll be working on your project.
