Geotechnical Site Investigations

Atlas Engineering and Technology Group (AETG) offers comprehensive geotechnical site investigations customised for Sydney's geological conditions. We provide accurate subsurface characterisation for informed decision-making, utilising robust equipment and methodologies that comply with AS 1726:2017.

We offer a full suite of geotechnical investigation services covering every stage of subsurface assessment.

Australia's geological landscape is diverse, showcasing a variety of soil types and geological formations, from the soft, alluvial soils that blanket the coastal regions to the expansive reactive clay soils found across much of the continent. Because of this vast variability, comprehensive site investigations are essential for understanding the specific conditions at each location and ensuring safe and effective development.

Comprehensive Field Testing

Our experienced field teams employ a range of advanced techniques to gather in-situ data, providing a realistic picture of ground conditions:

  • Boreholes and Test Pits: Direct soil profiling, sampling, and groundwater monitoring.
  • Cone Penetration Testing (CPT): Rapid soil stratigraphy and geotechnical parameter profiling.
  • Standard Penetration Testing (SPT): Assessment of soil density and strength.
  • Pressuremeter Testing: In-situ soil and rock stress-strain characterisation.
  • Vane Shear Testing: Undrained shear strength measurement for cohesive soils.

Comprehensive Laboratory Testing

Samples collected in the field are rigorously tested in our accredited laboratory to determine key soil and rock properties:

Soil Classification and Index Properties

Soil classification is essential for understanding soil behavior in engineering applications. The index properties help to determine soil types, predict behavior under load, and make informed design decisions.

Particle Size Distribution (Sieve & Hydrometer)

Particle size distribution reveals the relative proportions of different-sized soil particles. This fundamental test provides insight into a soil's drainage, strength, and compaction characteristics.

The soil is passed through progressively finer mesh sieves in a sieve analysis. The particles retained on each sieve are weighed, and percentages are calculated to create a grain-size distribution curve. This method works well for coarse-grained soils (sand and gravel).

For fine-grained soils (silts and clays), hydrometer analysis becomes necessary. This test relies on Stokes' Law, which describes how particles settle in a liquid. Engineers can determine the distribution of fine particles that would pass through the smallest sieve by measuring the density of a soil-water suspension over time.

Atterberg Limits

Atterberg limits characterize how fine-grained soils behave at different moisture contents. As water content changes, soil transitions between solid, semi-solid, plastic, and liquid states.

The key Atterberg limits include:

  1. Liquid Limit (LL): The moisture content at which soil transitions from plastic to liquid state, measured using a Casagrande device or fall cone test.
  2. Plastic Limit (PL): The moisture content at which soil transitions from semi-solid to plastic state, determined by rolling soil into 3mm threads until they crumble.
  3. Shrinkage Limit (SL): The moisture content below no further volume reduction occurs as the soil dries.

Data Analysis and Reporting

We transform raw data into clear, actionable insights, providing you with comprehensive geotechnical reports that include:

  • Detailed Borehole Logs and Cross-Sections: Visual representation of subsurface conditions.
  • Geotechnical Models and Parameter Determination: Key parameters for engineering design.
  • Site Classification per AS 2870: Foundation design guidance for residential projects.
  • Hazard Identification and Risk Assessment: Identification of potential geotechnical risks and mitigation strategies.

Our reports are meticulously prepared, clearly presented, and tailored to your project requirements. They provide the geotechnical intelligence you need to progress confidently.

Industry Sectors We Serve

AETG provides geotechnical site investigation services across a wide range of sectors, including-

  • Transportation: Roads, Railways, Ports, Airports, Bridges, Tunnels, Shafts
  • Building & Development: Industrial, Commercial, Government, Private Buildings & Land
  • Water Infrastructure: Dams, Pipelines, Tunnels, Directional Bores

Why Choose AETG for Your Geotechnical Site Investigation?

  • Deep understanding of Sydney's specific geological challenges.
  • Adherence to AS 1726:2017 and rigorous quality control.
  • Qualified geotechnical engineers and experienced field technicians.
  • Utilizing state-of-the-art equipment and methodologies.
  • Investigations customized to your project's specific needs and budget.
  • Clear, concise reports providing practical recommendations.
  • Dedicated to providing exceptional service and support throughout your project.