PREDICTION OF COMPACTION CHARECTERISTICS OF SOIL USING PLASTIC LIMIT

Abstract

In all kinds of earthwork constructions, the laboratory determination of the compaction characteristics of the soils plays an important role. Soil compaction is defined as the method of increasing the density of the soil by application of mechanical energy. The principal reason for the compaction of the soil is to produce a soil mass which can satisfy the three basic criteria. Firstly, the reduction of subsequent settlement of the soil mass, under working loads. Secondly, for the reduction in permeability which will subsequently avoid built up of large water pressures causing liquefaction problems and is also important for retaining water in case of earth dams. Thirdly, it is used for increasing the shear strength of the soils. But the determination of compaction characteristics in laboratory is laborious. It requires significant time and effort. Hence, there is a necessity for prediction of compaction characteristics with the help of correlating it with index properties of soil which can be determined easily. The plastic limit of soil can be found effortlessly and it bears a good correlation with compaction characteristic, namely optimum moisture content (OMC). In this paper, a study is conducted on nine types of fine grained soils like black cotton soil, red clay, china clay, marine clay, silty clay etc. collected from different parts of Telengana and Andhra Pradesh. And a simple equation has been suggested using regression analysis to obtain the optimum moisture content of a soil from the plastic limit, thereby eliminating the dependence of the proctor test for determination of OMC.