EVALUATION OF COMPRESSION INDEX OF ADDIS ABABA RED CLAY SOILS FROM LIQUID LIMIT

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Author/s

Solomon Desta and Samuel Tadesse

Abstract

It is a common practice to use empirical equations in computing engineering properties of soils in geotechnical engineering and we usually use such empirical formulae that are developed in other countries, particularly those countries found in the temperate zone. However, it is noticeable and apparent that these empirical formulae are site specific and give a better result for soils from which they are formulated and hence it may be erroneous to use them as they are for our soils which have, in most cases, dissimilar properties. Most of the existing correlation relationships which are used for the estimation of compression index of clay soil in terms its index properties are of linear in form. In this study, with the objective of predicting the compression index value from index properties of Addis Ababa red clay soil, laboratory tests on remolded samples have been carried out and few data were collected from previous study and the subject study has been carried out on data points or sample size of 30. A software package named SPSS has been utilized to undertake the regression analysis. In analyzing the regression, the independent variable considered is Liquid Limit (LL) and the variable to be predicted (dependent variable) is Cc. A relatively strong correlation was established between Cc and LL with coefficient of determination of 0.664 for a total sample size of 30.