The size of the ballast used in railway track varies from 1.9 cm to 5.1 cm. The stone of size larger than 5.1 cm is not preferable due to poor interlocking property.
The coefficient of permeability of soil(K) can also be computed from several empirical formulae, which are given below:
1. Jaky’s Formula.
2. Allen Hazen’s Formula.
3. Terzaghi’s Formula.
4. Kozney’s Formula.
5. Louden’s Formula
In this article, we are going to discuss about the capillarity permeability test or the horizontal capillarity test, which is another one method used for determining the coefficient of permeability as well as the value of capillarity height of the soil sample.