Melbourne's rapid growth since the Gold Rush era has pushed development onto the expansive basaltic clays of the west and the silty alluvium of the Yarra corridor. These soils respond dramatically to moisture changes, which is why we run Atterberg limits on every clay-bearing sample before any foundation design. The liquid limit and plasticity index tell us whether a soil will shrink, swell, or hold its shape under load. Without that data, you are guessing at bearing capacity. We complement this with a sieve analysis for particle size distribution and a Proctor test to establish optimum moisture for compaction, creating a complete geotechnical baseline for your project.
Clays with a plasticity index above 35 in Melbourne's west typically require lime treatment before they can be used as engineered fill.