Albury-Wodonga grew rapidly after the railway arrived in the 1880s, turning a river crossing into a regional hub. The city sits on the Murray River floodplain, with alluvial clays and silts over weathered granite. That geology creates real challenges for foundations and earthworks. We use the Flat Dilatometer Test (DMT) to map lateral stresses and stiffness in these soils. It is fast, repeatable, and gives a continuous profile from 0.2 m down to 30 m. Before you design a retaining wall or slab, a DMT run reveals how the ground will react under load. For shallow foundations we often pair it with a vane shear test to confirm undrained strength in the clay layers.
The DMT gives a continuous stiffness profile every 20 cm — ideal for soft alluvium where SPT blow counts scatter.
Methodology and scope
Local considerations
A three-storey commercial building on David Street in Wodonga settled 40 mm after construction — the foundation was designed on SPT N-values that missed the low-strain stiffness. The alluvial clay there is sensitive: remoulding drops its strength by half. A DMT before piling would have shown the true K₀ and constrained modulus. Without that data, the design underestimated lateral movement under the adjacent road. We see this pattern across the floodplain. The DMT catches the soft zones that SPT blows simply punch through. It is one of the few in-situ tests that directly measures horizontal stress, which controls wall deflection and pile group behaviour.
Applicable standards
AS 1289.6.5.2 – Standard Test Method for Performing the Flat Plate Dilatometer, AS 1726:2017 – Geotechnical Site Investigations, AS 4678:2002 – Earth Retaining Structures
Associated technical services
Full DMT Profile with Interpretation
Continuous profiling every 20 cm from surface to target depth. Includes real-time data logging, Marchetti correlations for M and Su, and a report with depth plots of KD, ID, ED, and derived parameters. Suitable for detailed foundation design and settlement analysis.
DMT + Laboratory Calibration Package
Combines the DMT run with index and strength tests on undisturbed samples taken at selected depths. We correlate DMT results with triaxial and consolidation data to refine the design parameters. Ideal for projects where the ground model must be validated for regulatory approval.
Typical parameters
Frequently asked questions
How deep can the Flat Dilatometer Test reach in Albury-Wodonga alluvium?
The blade can be pushed to 30 m in soft to firm clays and sands. In the stiff desiccated crust near the surface we sometimes pre-drill a small pilot hole to avoid blade damage. The 20 cm interval gives a very detailed picture of layer changes — much better than the 1.5 m spacing of a standard SPT.
What parameters does the DMT measure that I cannot get from SPT or CPT?
The DMT is the only common in-situ test that directly measures horizontal stress index (KD). From that we derive K₀, which controls lateral earth pressures on retaining walls and piles. It also gives constrained modulus (M) for immediate settlement, something neither SPT nor CPT provide without site-specific correlations.
How much does a DMT survey cost in Albury-Wodonga?
A typical DMT sounding to 15 m depth costs between AU$1,400 and AU$1,800, including mobilisation within the Albury-Wodonga urban area. The price covers setup, real-time data logging, and a report with interpreted profiles. For deeper holes or multiple test locations the per-point rate decreases.