Further Developments in the Correlative Study of Vertical Collapse Percentages in Collapsible Soils

The Israeli model for the vertical collapse percentage of collapsible soil subgrades was published in 2013. Since then, new collapse test results have become available (all together, for 147 undisturbed and remolded silt or silty clay specimens with full results, and for 188 specimens with partial results), enabling an updating of the existing collapse model and, consequently, the obtaining of a more accurate prediction of vertical collapse under a given vertical pressure. This paper concentrates on an additional and entirely new collapse model of a pure linear nature in order to further enhance prediction accuracy. The final recommendation is to use both the new updated vertical collapse model and the new linear model together with the limited local collapse tests results of a given project. As shown, this is to be done in a combined way that adjusts both the new updated and the linear models to fit the specific collapse characteristics of the given project.