Investigations into factors in uencing the CBR values of some Aegean sands

The California Bearing Ratio (CBR) value of the soils is very important for geotechnical engineering and earth structures. A CBR value is aected by the soil type and dierent soil properties. With this in view, in this paper, an attempt has been made for investigating the factors that aect the CBR values of some Aegean sands collected from nine dierent locations in Manisa (Turkey). The sand samples were tested for mineralogy, particle shape and size, and specic gravity. The CBR tests were then performed on these samples at dierent dry densities to examine the in uence of dry density, relative density, water content, and particle shape and size on the CBR value. Multiple Regression Analysis (MRA) was performed to predict the CBR value of the sands by using the experimental results. Moreover, several performance indices, such as coecient of correlation and variance account for mean absolute error and root mean square error, were calculated to check the prediction capacity of the proposed MR equation. The obtained indices make it clear that the equation derived from the samples used in this study applies well, with an acceptable accuracy, to the CBR estimation at the preliminary stage of site investigations.