Engineers Australia

A chart to estimate CBR of plastic soils: A case-study from Queensland, Australia

Ivan Gratchev, Sameera Pitawala, Netra Gurung and Errol Monteiro


California Bearing Ratio (CBR) is an important parameter used in design but it is tedious and time-consuming to obtain. This technical note presents and discusses the results of laboratory tests which were performed on plastic soils to identify the soil parameters with a high degree of correlation with CBR. Analysis of the obtained data and the relevant literature resulted in a chart that can be easily used to estimate the CBR of soil based on its plasticity and optimum moisture content.