Geotechnical Engineering

We offer geotechnical services to a variety of industries, including land development, landfills, quarries/mining, transport, energy, and more.

Providing specialised advice such as stability assessments, remedial and detailed design, emergency response, forensic geotechnical engineering and development of comprehensive solid waste management plans.

Services that we provide:

Engineering Geology

Mapping – land-based, aerial imagery, UAV (Un-personed Aerial Vehicle or drone), geospatial analysis and digital remote sensing (photogrammetry/LIDAR (Light Detection and Ranging) and InSAR (Interferometric Synthetic Aperture Radar))
Geomorphology
Landslides assessments
Surface and subsurface erosion – including geophysics interpretation
Rock slopes
Faults
Aggregate quarry resources and road construction materials

Geohazards and Lifelines

Geohazard identification and risk assessment for lifelines, infrastructure and mining/quarrying including high-pressure gas/petroleum products and water pipelines. This type of work is crucial post a Civil Defence event such as the recent Nelson & Northland floods.
Corridor hazard, route selection and options assessments
Climate change implications
Landslide, soil slope and rock slope stability assessments
Coastal cliff hazard and risk assessments
Emergency response and assessment

Remedial & Detailed Design

Landslide stabilisation – drainage, buttress/retention, shear keys, soil nails
Rock slopes – rock anchors, bolting, shotcrete, mesh, abseil rock scaling, rockfall catch fences, rockfall bunds
Ground improvement/problem soils – liquefiable ground, re-use of existing materials – sustainability
Geosynthetic applications – including geogrid reinforced gravel rafts
Deep foundation/excavation support and temporary support – sheet piles
Earth retaining structures – retaining walls, gabions, MSE walls
Dams, embankments, ponds, canals, tailings facilities and waste rock disposal
Stream and coastal erosion protection
Earthworks specifications
Erosion and sediment control
PS1 (Design) and PS2 (Design Review) sign off and tender evaluation

Construction Monitoring

Remedial works procurement (tender) process
Engineer To the Contract (ETC)
Contractor liaison, construction supervision/monitoring and as-builting
PS4 sign off

Geotechnical Monitoring

Monitoring for geohazards, dams and remedial works

Movement networks (survey, manual and automated)
Piezometers and transducers
Inclinometers and extensometers
Rainfall gauges
Drain and stream flow recording
Remote monitoring systems

Geotechnical Investigations

Desktop review and mapping
Perform/supervise/log hand augers, scala penetrometer, drilling, CPT, test pits/open excavations and geophysical (surface and downhole)
In situ sampling and testing – permeability, nuclear densometer, compaction trials, clegg hammer
Out-sourced laboratory testing including acid sulphate soils

Ground Models, Stability Assessments and Geotechnical Reporting

Landslides in all geological terranes
Rock slopes – cuttings, quarries, open pit mines, rock mass classification
Kinematic assessments including rockfall analysis
Seismic assessments – liquefaction induced ground settlements, lateral spreading/stretch, fault rupture risk
Subsurface and surface erosion – including tomos
Deep and shallow excavations/foundations and piles
Earth dams, embankments, ponds, canals – condition assessments and optimizing of existing structures, breach modelling
Rivers and streams – erosion, flooding, accretion surveys and stop banks
Mining waste rock stack/dump design (co-disposal), tailings dam surveillance, safety and stability risk assessments
Dewatering drawdown and settlement, seepage and inflow
Resource delineation for aggregate quarries and roading construction materials
Land development foundations, retention (retaining walls) and ground improvement – residential/commercial/industrial
Road foundation assessments – green and brown fields
Ground support, HDD, pipe jacking

Solid Waste

Site Investigation
Waste assessments
Landfill engineering design
Liner design – natural and geosynthetic
Management plans
Bond assessment

Emergency Event Response and Specialist Advice

Rapid incident/event response
Forensic geotechnical engineering
Insurance claims post failures
Resource consent reviews
Climate change risk assessments – geohazards

Related projects

Perris Road Landslide Remediation

PDP completed a project addressing a landslide that affected critical gas and petroleum products pipelines north of Auckland.

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Awakau Road - Safeguarding critical energy infrastructure with PDP's slope stabilisation solutions

Back in 2020, PDP completed a project for Firstgas to enhance the resilience of its transmission pipeline network in the North Island, which is essential to supplying natural gas to kiwi homes, businesses and major industry throughout the North Island.

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Blockhouse Bay Multi-Unit Residential Development

In 2024, Kāinga Ora engaged PDP to deliver comprehensive geotechnical services for a new housing project: a 68-townhouse development and an extension of an existing residential road.

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Haumingi 9B3B Papakāinga Development – Geotechnical and Seismic Assessment

PDP undertook a geotechnical and seismic desktop assessment for a proposed papakāinga development located on an elevated terrace overlooking Lake Rotoiti.

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Grafton Road Wellington - Rock Slope Stabilisation

In 2022, Wellington City Council engaged PDP to assess and remediate slope stability risks to the road for a greywacke (siltstone and sandstone) slope cut at 60° – 80° along a 68 m length of Grafton Road, Wellington.

Find out more