New Conditioned Soil Index Test and Characteristic Ground Movement Calculation Model

This paper presents a new laboratory test method for determining the soil index of expansive clays. This method is suggested to replace the shrink-swell, loaded shrink, and unloaded shrink tests methods presently being used in Australia standard 1289 in an effort to solve some problematic issues identified in testing highly expansive clays. The research for this test has been carried out by the authors in a particularly high expansive clay area in Melbourne, Australia (liquid limits 70–120%+) derived from the in-situ weathering of neogene age basalts. The main aim of the investigation was to determine the values and variability of the soil indices in a large residential basaltic province and develop a speedier and more accurate method which can be widely used commercially to plot suction/shrink relationships and test the soil indices. A secondary aim was to develop a new model to calculate and the ground characteristic movement (y_s) for site characterization.