Shepparton sits on deep Quaternary alluvium of the Goulburn River floodplain, with interbedded clays, silts, and sands extending more than 30 m. The water table is typically shallow, between 1.5 and 3 m below ground, which makes conventional drilling messy and slow. That is where the CPT (Cone Penetration Test) becomes invaluable: it provides a continuous profile of soil behaviour type, undrained shear strength, and consolidation parameters without the disturbance of sampling. We routinely pair this technique with a calicata exploratoria to verify stratigraphy at critical horizons, especially where soft clays may control settlement. The local dairy and horticulture industries rely on flat, stable sites, so knowing the exact layering beneath a cold-store or packing shed is essential.
Fluvial deposits are notoriously variable; the CPT catches every sand lens and clay seam that a borehole would easily skip.
Method and coverage
Regional considerations
The difference between a site near the Goulburn River and one on the eastern rise is dramatic. In the river flats, soft clays with low undrained strength can cause excessive settlement under silo loads. On the higher ground west of the city, stiff clays with high plasticity shrink and swell with seasonal moisture. A CPT in Shepparton reveals these contrasts in a single push. Without it, a uniform design would either overcost the project or risk differential movement. We have seen sheds on the floodplain settle 150 mm while adjacent structures on the ridge stayed stable. The cone tells you exactly where the transition occurs, so you can tailor your footing depth and type accordingly. Ignoring that variability is the biggest risk in this region.
Standards that apply
AS 1726-2017 – Geotechnical site investigations, AS 4678-2002 – Earth-retaining structures, AS/NZS 1170.0-2002 – Structural design actions
Complementary services
Standard Electric CPT with Dissipation Tests
10-tonne cone pushed to refusal or target depth. Real-time data acquisition with 20 mm resolution. Dissipation tests at selected depths to estimate coefficient of consolidation. Suitable for soft to firm clays and loose to medium sands common in the Goulburn Valley.
Seismic CPT (SCPT) for Dynamic Properties
Adds a geophone array to measure shear-wave velocity during the cone push. Essential for earthquake site classification under AS 1170.4. Provides small-strain modulus (G0) for machine foundations and road subgrade design. Particularly useful near the Shepparton East industrial zone.
Typical parameters
Top questions
How deep can the CPT reach in Shepparton’s alluvial soils?
In the central floodplain we typically reach 20–25 m before hitting dense sand or gravel that stops the cone. In the western clay deposits we sometimes achieve 30 m. The depth depends on the cone size (10 or 20 tonne) and the exact stratigraphy.
What is the cost range for a CPT in Shepparton?
A standard CPT with dissipation tests ranges from AU$270 to AU$380 per sounding, depending on depth, access, and number of tests. Seismic CPT adds approximately AU$80–$120 per sounding. Bulk discounts apply for multiple soundings on the same site.
How does CPT compare to SPT for local projects?
The CPT gives a continuous profile with no sample disturbance, which is ideal for Shepparton’s thin sand lenses and soft clay layers. SPT provides disturbed samples for classification but only at 1.5 m intervals. For settlement analysis in the floodplain, the CPT’s continuous data is far more reliable.
Can I use CPT results for pavement design in Shepparton?
Yes. The cone data correlates directly with California Bearing Ratio (CBR) and resilient modulus for pavement design. We have developed local correlations for Shepparton’s soils that are accepted by the Goulburn Valley Highway Authority. A seismic CPT also gives dynamic modulus for heavy haul roads.