ABSTRACT
The Werribee Formation lies stratigraphically between the Lower Tertiary Older Volcanics and the Silurian siltstone, well below ground level over most of the study area. Engineering properties of the Werribee Formation have been assembled from various sources. Description of the soils in the Werribee Formation in terms of particle size distribution covers the full range of the silt and sand fraction as defined by AS 1289 with clay dominating many of the available grading determinations. Data on the consolidation characteristics of the Werribee Formation is limited. Estimates of the preconsolidation pressures from oedometer tests on the Werribee Formation were consistently over 800 kPa. In virtually all cases where the Werribee Formation is predominantly cohesive, it is of very stiff to hard consistency. Few construction projects have had significant excavation in or near the Werribee Formation apart from the Brooklyn Pump Well and the melbourne underground rail loop project.
