SITE INSPECTION & DENSITY TESTING

In Australia, residential and commercial projects' earthwork and site preparation shall follows NCC requirements in section of 'site preparation' and Australia standard: 'AS 3798-2007 Guidelines on Earthworks for Commercial and Residential Developments'. 


When a block of land is filled and prepared for construction, the quality of the compaction is checked through inspections and testing on site. The two main levels of supervision and testing are Level 1 and Level 2, and the difference in between is who controls the work and how strictly the fill is monitored, which will result in different quality and risk controls.

 

Why we need earthwork control? How we manage it?


The Critical Importance of Earthwork Control 

Before construction begins, proper earthwork inspection and testing ensures:


  • Structural integrity of foundations
  • Prevention of costly future damage (cracking, subsidence)
  • Compliance with Australian Standards (AS 3798)
  • Verification of proper compaction and fill quality

After we know the reason for our earthwork control, we need to know how we can control, there are two levels of quality controls: Level 1 and Level 2.

Level 1 vs. Level 2: Key Differences

Level 1: Strictly Controlled Fill (Higher Assurance)

Supervision/Testing/Compliance Statement:


  • Continuous on-site monitoring by Geotechnical Inspection and Testing Authority (GITA, like us).
  • GITA bear the responsibility for ensuring sufficient inspection and testing. Every layer of fill inspected and tested, strict moisture and density controls.
  • Detailed report covering all testing and inspections by GITA
  • Comprehensive compliance statement issued by GITA as per specification and drawings.

When Required:

  • High-risk sites
  • Reactive soil conditions
  • Critical infrastructure projects
  • Where maximum quality assurance is needed

Level 2: Standard Controlled Fill

  • Supervision/Testing/Compliance Statement:
  • Periodic sampling and testing conducted by Geotechnical Testing Authority (GTA, like us) when required by superintendent.
  • Contractor controls earthwork activities.
  • Spot testing at contractor's discretion, less frequent density checks.
  • Basic test certificates, No comprehensive compliance statement.

When Used:

  • Low-risk residential projects.
  • Stable soil conditions.
  • Smaller scale developments.
#COMPARING FACTOR
LEVEL 1
LEVEL 2
1Control Level
Strict (GITA supervised)
Basic by GTA (contractor managed)
2Test Frequency
Continuous
Periodic or when required by superintendent
3Documentation
GTA Compliance Statement
Test certificates only
4Cost
Higher
Lower
5Risk Control 
Better Risk Control
Less Risk Control

Important Note: Level 1 testing cannot be applied after earthworks are complete - the GTA must be present during all filling and compaction activities to issue their compliance statement.


Conclusion

For projects requiring maximum quality assurance, Level 1 earthwork inspection and testing with GITA supervision provides:


  • The highest standard of fill quality control
  • Comprehensive documentation for approvals
  • Protection against future structural issues
  • Peace of mind for developers and builders


For small projects with good soil and terrain conditions, Level 2 earthwork sampling and testing with GTA provides support for ensuring the compliance of drawings and specification.


Always consult with your geotechnical engineer early in the planning stage (like DA/CDC/CC stage) to determine the appropriate testing level for your specific site conditions and project requirements.


Contact us today to find out what we can help with your project.


JWH Engineering Pty Ltd