Correlation between CBR Values and Index Properties of Soils: A Case Study of Ibiono, Oron and Onna in Akwa Ibom State

This paper presents the results of the correlation between California Bearing Ratio (CBR) and index properties of soils. Laboratory tests were carried out to determine soaked CBR, LL, PL, PI, MDD and OMC on soil samples collected from Ibiono, Oron and Onna L.G.A. in Akwa Ibom State. A correlation relationship between CBR and soil index properties were developed using non-linear and multiple linear regression analysis. Standard Minitab 13 and Microsoft Excel 2013 software package were used for the analysis. It was shown that a high adjusted coefficient of multiple linear regression value R were obtained for Ibiono and Onna. Comparison between laboratory and predicted CBR values obtained from MLR models indicate that geotechnical properties; PI and OMC for Ibiono, OMC and MDD for Onna, LL, PL and OMC for Oron can be used to predict the soaked CBR values. R2 value of 0.942, 0.731 and 0.653 were obtained from the variation of actual laboratory CBR with predicted CBR for Ibiono, Onna and Oron specimen respectively. The correlation matrix between CBR and index/geotechnical properties; CBR, LL, PL, PI, MDD and OMC were observed to have high negative values.