Abstract
The consistency properties of fine grained soils are generally expressed by the plastic limit, the liquid limit and the plasticity index, and especially, Casagrande's plasticity chart based on the plasticity index and the liquid limit is widely used for the classification of soils. However, at present, it is impossible to guess quantitatively the mechanical properties of soils at the classification based on the plasticity chart. Therefore, the authors wish to identify the relation of the consistency properties to the mechanical properties of soils by means of the plastic ratio chart in which the abscissas represent the liquid limit and the ordinates the corresponding plastic ratio. After these considerations, it becomes clear that the plastic ratio as a new index property is effective for evaluating the consistency properties of soils, and the plastic ratio chart is also useful to estimate quantitatively the swelling capacity and the residual strength of soils.
