Model for the Prediction of California Bearing Ratio Using the Geotechnical Properties for Subgrade Soil

The subgrade soil is an important component of the pavement structure because it can affect the performance and durability of the road during the service life. One of the essential properties of the subgrade soil to evaluate the strength is the California bearing ratio (CBR). It is necessary to predict the CBR of any soil to determine its suitability as subgrade soil before use. Therefore this study was to develop multiple regression model for prediction of CBR using the geotechnical properties of the soils. The tests carried out in the study were consistency limis, particle size analysis, compaction and CBR tests. It was found that the soils were characterized to range from very poor to excellent for subgrade purposes. The coefficient of correlation, coefficient of determination and standard error of the model were found to be 0.834744, 0,696797 and 10.28991 respectively. Also, all the dependent variables were very significant in predicting the California bearing ratio.