Site Investigation
Geotechnical site investigation is the process of exploring and analysing the physical properties of soil, rock, and groundwater beneath a proposed development site, enabling a deep dive into what lies beneath the surface.
Essentially, what is built above ground is only as strong as what supports it below.
CMW Geosciences has large geotechnical site investigation teams located across Australia and New Zealand who undertake SI activities across a wide variety of terrain and geological environments.
Site investigation can be carried out in a variety of ways and includes:
Desktop studies
Reviewing geological maps, historical data, and previous reports.
Site reconnaissance
Observing terrain, drainage, vegetation, and signs of instability.
Site/field investigations
Drilling boreholes, excavating test pits, and conducting in-situ tests and sampling such as Cone Penetration Tests (CPT) and Standard Penetration Tests (SPT).
Laboratory testing
Analysing soil and rock samples for strength, density, permeability, and compressibility.
Groundwater assessment
Measuring water levels, flow, and pressure.
This in turn supports design optimisation by enabling engineers to tailor foundations, retaining walls, and earthworks to actual ground conditions, saving time and money.
Geotechnical investigations are critical to project success by reducing risk and identify geotechnical hazards such as soft soils, groundwater issues, or unstable slopes before construction begins.
A site investigation also assists with regulatory compliance to meet the requirements of Standards such as AS 1726 in Australia and NZGS guidelines in New Zealand, helping secure approvals faster.
By providing accurate subsurface data, geotechnical investigations help project owners avoid costly surprises during construction.
Geotechnical site investigation is the blueprint for building safely, smartly, and sustainably.
Investigation techniques
Our CMW Geosciences site investigation team employs a full range of ground investigation techniques to suit project geology and complexity.
These include:
- Wireline diamond core drilling (HQ, NQ & PQ)
- Solid and hollow auger borehole drilling
- Hand auger borehole drilling
- Cone Penetrometer Tests (CPT) with or without pore pressure measurements
- Backhoe and hydraulic excavator test pits and trenches
- Bulldozer costean excavations
- Geophysics
We also have strong relationships with specialist drilling and jack-up barge contractors to execute nearshore drilling investigation programs.
These relationships are the result of our experience in procuring and running extensive and complex geotechnical investigation programs.
In-situ testing and sampling methods include:
- Standard Penetration Tests (SPTs)
- Dynamic penetrometer testing, including Dynamic Cone Penetrometer (DCP) and Perth Sand Penetrometer (PSP) tests
- Plate Load Tests, including collapse potential
- Falling head and rising head field permeability tests, pump tests
- U50 sampling including use of 1-way valves for soil recovery in soft / saturated soil
- Block sampling (test pits) for collapse potential
Environmental
CMW Geosciences has well-established relationships with specialist environmental consultancies, and our teams regularly collaborate to provide a more cost-effective investigation program.
Laboratory testing
Our CMW Geosciences team works closely with several NATA-accredited geotechnical testing laboratories to offer a full range of soil, rock, aggregate and concrete tests.
