Dominant Parameters Controlling the Permeability of Compacted Fine-Grained Soils

Abstract

Permeability behaviour of compacted fine-grained soils has immense practical importance in view of the performance of various geotechnical engineering structures such as embankments, earth dams, sub-grades of pavements, compacted clay liners at land fills and the like. Many factors appear to control the permeability behaviour of compacted fine-grained soils. The present paper discusses these factors critically with illustrations. Soils of same liquid limit level having almost same void ratio exhibit significantly higher values of coefficient of permeability on the dry side of optimum when compared with those on wet side of optimum. It has been brought out that void ratio is not the only factor controlling the coefficient of permeability. But it is the soil fabric/effective pore size which controls significantly the coefficient of permeability at the same void ratio level. It has been further brought out that placement condition, soil fabric, effective pore size, clay mineralogical composition and void ratio appear to control the coefficient of permeability in the order of their importance.