Prediction of the California bearing ratio from some field measurements of soils

Abstract

In this study, the fast and safe predictability of the California bearing ratio (CBR) from some important soil parameters that can be obtained easily and cheaply was investigated. Within the scope of this study, the CBR values of 21 different soils in different regions of Sivas province (Turkey) were determined in situ by CBR tests. Then, standard penetration tests (SPT) and ground vibration measurements were conducted on the same soils. At the same time, some physical properties of the soils were determined as a result of field and laboratory studies. Regression analyses were carried out in order to develop correlations between the CBR, and field and laboratory study results. Significant and highly correlated relations between the CBR and peak particle velocity, blow number (SPT-N value), water content (w) and dry unit weight(γd), were obtained. Prediction performance of all proposed equations were tested by using the root mean square error (RMSE) and variance account for (VAF) indices, and particularly, correlations obtained between the CBR – ground vibration and CBR – standard penetration values were observed to have high prediction performance. Good performance indices (correlation coefficients, RMSE, VAF) indicate that the CBR values of soils can be used for initial assessment.