Bendigo's geology is a patchwork of deeply weathered Ordovician turbidites, with shallow bedrock often masked by clay-rich colluvium and alluvial flats along Bendigo Creek. That variability makes the Ménard pressuremeter test (PMT) a smart choice when you need in-situ stiffness and strength data without hauling samples to a lab. The probe expands directly against the borehole wall, giving us a complete pressure-volume curve. For a project near the town centre we ran PMT alongside ensayo CPT to cross-check both deformation modulus and cone resistance across the same profile.
The PMT gives you a direct measurement of soil stiffness and limit pressure, not an interpretation of blow counts.
Methodology and scope
The local soils in Bendigo typically show a shear strength increase with depth, but the gold-bearing quartz reefs create irregular hard zones that fool standard penetration tests. The PMT measures two key parameters: the Ménard modulus (E_M) and the limit pressure (p_L). From those we derive the rheological coefficient and the net limit pressure used in bearing capacity calculations. We follow AS 1726 and the Ménard rules for drilling the pocket, ensuring the borehole diameter stays within 5% of the probe size. A typical output table looks like this:
Depth range: 2.0 – 12.0 m
E_M range: 4.5 – 28.0 MPa
p_L range: 0.6 – 2.1 MPa
Pre-bore diameter: 66 mm
Test type: A (standard), B (soft rock)
Technical reference image — Bendigo
Local considerations
A commercial development in the Epsom area had foundation loads of 1.8 MPa on stiff clay. The boring logs showed refusal at 4 m on what looked like bedrock. We ran the Ménard pressuremeter test (PMT) in two adjacent holes and found E_M values dropping from 22 MPa at surface to 6 MPa at 3.5 m. The 'refusal' was a quartz-rich boulder, not rock. Relying on SPT refusal alone would have led to a footing design with 40% less capacity than needed. The PMT caught it in time.
Pre-bored pocket with AX or BX diameter, pressure-volume curve recording at 0.5 m intervals. Data reduction includes E_M, p_L, and creep pressure. Suitable for stiff clays, sands, and weathered rock in Bendigo.
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PMT with seismic module (S-PMT)
Combines the standard pressuremeter with a downhole seismic source to measure vs30/" data-interlink="1">shear wave velocity at each test depth. This gives G_max values alongside the Ménard modulus, useful for dynamic design in seismic zones.
Applicable standards
AS 1726 – Geotechnical site investigations, AS 1289 – Standard test methods for prebored pressuremeter testing in soils, NF P94-110 – Ménard pressuremeter test (French standard, reference method)
Frequently asked questions
What does the Ménard pressuremeter test measure that SPT cannot?
The PMT measures the soil's deformation modulus and limit pressure directly from the expansion curve, not from a blow count. In Bendigo's variable ground, where quartz reefs and clay lenses alternate, the PMT gives a continuous stiffness profile that SPT cannot match.
How much does a PMT cost in Bendigo?
The typical cost for a Ménard pressuremeter test (PMT) in Bendigo ranges between AU$1,800 and AU$1,930 per test depth. The final price depends on the number of tests, borehole depth, and site access conditions.
At what depth range can the PMT be performed?
We routinely test from 2.0 m down to 15.0 m with standard drilling equipment. Deeper tests up to 30 m are possible with a hydraulic rig, though the confining pressure at depth does not affect the measurement because the probe is pre-bored and expanded laterally.
Do you need special borehole preparation for the PMT?
Yes, the borehole must be drilled to a precise diameter with minimal disturbance to the sidewall. We use a rotary drilling method with a coring barrel or a continuous flight auger, then clean the pocket with a sampler before inserting the probe. The pocket diameter must stay within 5% of the probe diameter.
