The Goulburn Valley floodplain around Shepparton creates a complex soil profile where fine-grained flood deposits alternate with coarser river terrace sands. This sedimentary layering makes grain size analysis a critical first step in any geotechnical investigation here. The fine silt and clay fractions from overbank flooding can drastically alter soil behaviour under load, while the sandy lenses control drainage. Without a proper sieve and hydrometer test, you are essentially guessing at how these mixed soils will perform. We run the full procedure according to AS 1726, covering both coarse and fine fractions, and often pair it with a clasificación de suelos to assign accurate USCS or AASHTO groups before proceeding with foundation design.
In Shepparton alluvium, the hydrometer phase often reveals plasticity trends that the dry sieve alone cannot detect, especially with silt fractions above 30%.
Method and coverage
Regional considerations
A common mistake in Shepparton is relying only on the dry sieve for fine-grained alluvial soils. The hydrometer step is not optional here: it captures the clay-sized fraction that controls shrink-swell behaviour and frost susceptibility. If that fraction is underestimated, you risk designing for a soil that behaves completely differently when wet. The Goulburn Valley soils can show a plasticity index jump of 10 to 15 points once the full hydrometer curve is plotted. Missing that means your compaction targets, bearing capacity, and even pavement thickness designs could be off by a significant margin. We always run the full sieve-hydrometer combo on at least one sample per soil type encountered.
Standards that apply
AS 1726:2017 Geotechnical site investigations, AS 1289.3.6.1 Particle size distribution (standard method), AS 1289.3.6.1 (2007) Particle-size analysis of soils, AASHTO T-88 Particle size analysis of soils
Complementary services
Standard Sieve Analysis (Coarse Fraction)
Dry or wet sieving of samples from 75 mm down to 75 microns. Suitable for sands and gravels common in the Goulburn River terrace deposits. Includes Cu and Cc calculation.
Hydrometer Analysis (Fine Fraction)
Sedimentation test for particles below 75 microns. Essential for Shepparton's silt and clay alluvium. Provides the full clay-silt-sand distribution curve.
Combined Sieve-Hydrometer Report
Full particle size distribution from 75 mm down to 0.5 microns. Includes USCS classification, plasticity correlation, and compaction curve recommendations.
Typical parameters
Top questions
Why is the hydrometer test necessary for Shepparton soils?
Shepparton's alluvial soils from the Goulburn River contain significant silt and clay fractions that are too fine for the standard sieve to capture. The hydrometer test measures particles down to 0.5 microns, revealing the true plasticity and shrink-swell potential of the soil. Without it, the fine fraction is underestimated, leading to incorrect classification and foundation design assumptions.
How much does a grain size analysis cost in Shepparton?
The typical cost for a combined sieve and hydrometer analysis in Shepparton ranges from AU$170 to AU$330 per sample, depending on the number of sieves used, the need for hydrometer readings across 24 hours, and whether the sample requires pre-treatment for organic matter or soluble salts. Bulk discounts apply when testing multiple samples from the same site.
What standards govern grain size testing in Victoria?
In Victoria, the primary standard is AS 1289.3.6.1 for the particle size distribution test, which references AS 1726 for the overall site investigation framework. We also follow AS 1289.3.6.1 for hydrometer analysis and AASHTO T-88 where required by road authorities. All tests are performed under our NATA-accredited quality system (ISO 17025).