Estimation of soil compaction parameters based on Atterberg limits

Abstract

In civil engineering works, soils are commonly used as construction materials. Compaction of soils is carried out to improve the strength of the soils. However, compaction tests are time-consuming and relatively expensive especially when many samples are to be tested. In this study, an alternative method is proposed. The relationships of liquid limit, (LL), plastic limit, (PL), and plasticity index, (PI) to modified maximum dry density, (MDD), and optimum moisture content, (OMC), were determined. The parameters can therefore be correlated by graphical and empirical analysis. Using curve fitting techniques, empirical equations were obtained and charts were prepared. From these, it is possible to estimate the potential optimum moisture content and maximum dry density for the Modified and Standard Proctor compaction tests from the information of Atterberg limits only. Determination of Atterberg Limits is easier and the tools for the test are not complex, it therefore will save time and cost. The collected data for the study were obtained from government agencies and private sectors. The collected data then were used to produce the regression equations. While, the results of the laboratory test programme were used to compare with the results of the regression equations for the compiled data. In the study, the types of soil were limited for clay and silt only, i.e., cohesive soils. From the study, the results show that the multiple-parameter relationships are better than the single-parameter relationship because of its higher regression factor in the statistical analysis and lower percentages of differences in comparison with the laboratory results and the charts. The results also show that the R squared values obtained for the correlations between maximum dry density and the Atterberg limits are higher than that of for the correlations between the optimum moisture content and the Atterberg limits. Hence, optimum moisture content is not a good indicator compared to the maximum dry density parameter, for the estimation of the soil compaction parameters based on Atterberg limits.