Empirical correlations between engineering properties and index properties of soils

Abstract

The variations of compression index (Cc) and the coefficient of consolidation (Cv) with pressure are examined in this paper in the light of the mechanisms governing the compressibility of fine-grained soils. It is seen that both Cc and Cv are not constants for a given soil, as is normally assumed, but functions of the normal pressure. The manner of variation of Cc and Cv with consolidation pressure is not unique but depends on clay type. The compression index and the coefficient of consolidation increase with pressure for soils whose compressibility behaviour is governed by mechanical factors. For those soils whose compressibility behaviour is governed by physico-chemical factors Cc and Cv are found to decrease with increase in pressure. The study highlights the need to develop correlations, which can capture the trends of variation of Cc and Cv with consolidation pressure.