For any project in Albury-Wodonga that requires reliable soil strength and consolidation parameters, undisturbed sampling with Shelby tubes is the only way to get lab results that truly represent in-situ conditions. We follow AS 1726-2017 for sample classification and handling, and our NATA-accredited laboratory ensures the tubes are extruded and tested within the recommended time window. Before we order a Shelby tube run, we usually pair it with a calicatas exploratorias to log the stratigraphy first, then decide the exact sampling depth. The combined approach saves time and avoids wasting tubes on disturbed or gravelly layers that would ruin the sample anyway. In Albury-Wodonga, where the Murray River floodplain deposits alternate with stiff clays from the Tertiary age, undisturbed sampling becomes critical for settlement analysis under any medium to heavy structure.
In Albury-Wodonga, undisturbed Shelby tube sampling is the only reliable method to obtain true consolidation parameters for settlement design on Murray River floodplain clays.
Methodology and scope
Local considerations
Compare the soils in West Albury versus Lavington. West Albury sits on recent floodplain clays with high plasticity and low undrained shear strength — exactly the kind of profile where a disturbed sample would give you unconservative stiffness values. In Lavington, on the other hand, you hit residual basaltic clays that are stiff but highly reactive to moisture changes. If you rely on bulk disturbed samples for those clays, you will underestimate the swelling potential and probably end up with a cracked slab. Undisturbed sampling with Shelby tubes captures the fabric and fissures that control strength and volume change in both scenarios. Without that level of detail, the geotechnical model is guesswork, and the structural engineer has no basis for a rational foundation design.
Applicable standards
AS 1726-2017 – Geotechnical site investigations, AS 1289.6.0 – Standard practice for thin-walled tube sampling, AS 4678-2002 – Earth-retaining structures (reference for design parameters derived from undisturbed samples)
Associated technical services
Standard Shelby tube sampling (76 mm ID)
For routine projects in clay and silt profiles. We use a 76 mm internal diameter tube with a 1.5 mm wall, pushed hydraulically to preserve the natural structure. Ideal for consolidation and triaxial testing on medium to high plasticity soils.
Large-diameter undisturbed sampling (100 mm)
When the project requires larger specimens for direct shear or cyclic triaxial tests, we switch to a 100 mm diameter tube. This is common for pavement subgrade studies on the Hume Highway corridor or for tailings dam investigations in the region.
Piston sampler (fixed-piston type)
For very soft or sensitive clays — like those found in the Murray River backswamps — a fixed-piston sampler minimises disturbance during insertion and withdrawal. The piston remains stationary while the tube advances, preventing suction loss and maintaining the sample's integrity.
Typical parameters
Frequently asked questions
How much does undisturbed Shelby tube sampling cost in Albury-Wodonga?
The cost for undisturbed sampling ranges from AU$610 to AU$1,390 per sample, depending on depth, access conditions, and whether the tube is pushed from the surface or down a borehole. The price includes the tube, hydraulic push, on-site sealing, and transport to the lab. Volume discounts apply for multi-tube campaigns.
What is the difference between a disturbed and an undisturbed sample?
A disturbed sample — taken from a test pit or a split-spoon — has its structure, fabric, and in-situ water content altered during extraction. It is useful for classification tests (grading, Atterberg limits) but not for strength or consolidation parameters. An undisturbed sample, retrieved with a Shelby tube, preserves the soil's natural density, fissures, and cementation, so lab tests yield values representative of the ground as it exists.
When should I order undisturbed sampling instead of SPT or CPT?
Order undisturbed sampling when you need consolidation parameters (Cc, Cv, OCR), undrained shear strength from triaxial tests, or swelling pressure data. SPT and CPT give you index values and profiles but cannot provide the true stress-strain behaviour for settlement or bearing capacity design. If the design requires finite element analysis or a settlement prediction, you need undisturbed samples.