A Modified California Bearing Ratio Test for Granular Materials
It is known that laboratory and field tests, under saturation conditions, yield different California Bearing Ratio (CBR) test values for granular material. This is due primarily to the higher laboratory strength of the specimen confined in a rigid cylinder. A laboratory procedure is outlined by which specimens are subjected to controlled lateral pressure. A formula is proposed for determining design values from the modified laboratory data on the basis of theoretical bearing capacity considerations through the theory of plasticity. Test results are reported and the verification of the suggested method for determining the design CBR value of granular material is shown.