Material Suitability Assessments

Material suitability assessment is a vital process that certifies the proposed fill material for use as engineered or structural fills. Structural fill plays a crucial role in achieving accurately shaped landforms for building high-standard structures while minimising the risk of ground movements that could cause unexpected damage to shallow foundations. Earthworks are carried out in accordance with Australian Standard AS 3798 (Guidelines on earthworks for commercial and residential developments), which stipulates the minimum acceptable criteria for structural fills. Structural fills must be free of deleterious materials, have an appropriate level of internal friction, cohesion, and plasticity. These specifications must be meticulously determined by a suitably qualified Geotechnical Engineer, specifically for the proposed development.

While parameters related to highway embankments are not always relevant for fills on which buildings will be constructed, more stringent specifications are needed for building purposes. This is because highway schemes are considered major projects in civil engineering, whereas schemes involving low-rise buildings constructed on engineering fills are comparatively smaller in scale. However, control procedures must be appropriate for the project’s size and the criticality of the settlement tolerance.