Methodology
Our methodology for standard penetration test (SPT) in Mildura follows rigorous field procedures as per Australian Standard AS 1289.6.3.1. We employ a 63.5 kg hammer with a 760 mm drop to drive a split-spoon sampler, recording blow counts at 1.5 m intervals to obtain N60 values. Soil samples are retrieved for laboratory classification, including moisture content, Atterberg limits, and particle size distribution. For detailed profiling, we integrate SPT results with cone penetration test (cpt) data to correlate soil behavior and stratigraphy. Our team ensures borehole depths typically range from 10 to 20 meters, adapting to site conditions. All equipment is calibrated and maintained to guarantee reliable data for foundation design and seismic assessments.
Reference Technical Parameters
| Parameter | Reference Value |
|---|---|
| Predominant soil type | Alluvial silty clay and sand with gravel layers |
| Maximum seismic acceleration (PGA) | 0.10 g (AS 1170.4, Zone B) |
| Typical groundwater level | 2–5 meters below ground surface |
| Bedrock depth | >30 meters (sedimentary sequence) |
| Typical N60 range | 5–15 (clay), 15–30 (sand) |
Local Considerations — Mildura
Mildura's soil conditions are dominated by Murray River alluvium, with interbedded silts, clays, and sands. The shallow groundwater table, typically 2–5 m deep, requires dewatering measures for excavations. Seismic hazard in the region is moderate, with a PGA of 0.10 g per AS 1170.4 (Zone B). Our team has extensive experience in subdivisions and commercial developments, where standard penetration test (SPT) data is crucial for footing design and slab-on-grade foundations. For complex projects, we coordinate with our standard penetration test en Adelaide office to leverage regional expertise. The presence of reactive clays necessitates careful assessment of soil volume change potential.
Request a Quote
Our team reviews your project and issues an initial report at no cost.
Or write us directly at [email protected]
Services in Mildura
Applicable Standards
- AS 1726:2017 Geotechnical site investigations
- AS 1289.6.3.1:2004 Determination of penetration resistance (SPT)
- AS 1170.4:2007 Earthquake actions
- ASTM D1586 Standard Test Method for Standard Penetration Test (SPT)
Frequently Asked Questions
What soil types are commonly encountered in Mildura during SPT?
Mildura's subsurface typically consists of alluvial silty clays, sands, and gravels derived from the Murray River. SPT blow counts vary, with clays ranging N60 5–15 and sands 15–30. These conditions require careful interpretation for foundation design.
Is seismic assessment required for standard penetration test projects in Mildura?
Yes, Mildura falls under AS 1170.4 seismic Zone B with a PGA of 0.10 g. SPT data is used to determine soil site class (Ae to Ee) and assess liquefaction potential, especially in loose saturated sands.
What is the typical depth of SPT boreholes in Mildura?
For residential projects, boreholes are typically 10–15 m deep, while commercial or industrial sites may require depths up to 25 m to penetrate alluvial layers and reach competent strata. Groundwater levels influence depth and sampling intervals.