Dispersive soils are highly susceptible to erosion and internal instability when exposed to water. They can cause serious problems in earthworks, embankments, dam walls, and road subgrades if not identified and managed correctly. Western Geotechnical Laboratory Services (WGLS) provides accredited soil dispersion testing to AS 1289, including the Emerson Class Test (AS 1289.3.8.1) and Pinhole Dispersion Test (AS 1289.3.8.3). The Emerson Class Test is a quick, practical screening method that classifies a soil’s susceptibility to dispersion based on its behaviour in water. The Pinhole Dispersion Test provides a more detailed assessment by measuring the rate of erosion through a small hole in a compacted soil sample under flowing water. Together, these tests give geotechnical engineers the data needed to identify dispersive soils and specify appropriate treatment or design measures for dams, embankments, and earthworks across Western Australia.
