The present paper shows the understanding of factors that influence the value of the CBR test for fine and granular soils. This is important because the CBR test is frequently used in the design and evaluation of pavements. Nowadays, CBR tests are correlated with the resilient module, which is a key parameter in the current mechanistic methods of pavement design. However, the results indicate a large number of correlations depending on the modulus of elasticity and the plasticity indexes of the material that lead to a large dispersion of the results using these correlations. The above indicates that there are several variables that have not been taken into account in the correlations. The purpose of this study is to show how the value of the CBR test is a function of other variables such as the size and shape of the particles, the crushing, the compaction energy and the elastic behavior of the material. These variables were evaluated through FEM (Finite Element Method) simulations while varying several geotechnical parameters known in practical geotechnics. These simulations in FEM include a linear elastic model, a failure criterion (elastoplastic model), with isotropic hardening, in addition these were prepared for granular and fine soils. The results show that the CBR depends not only on the Young’s modulus (a parameter commonly used to correlate with the CBR), but also seems to depend on the compressibility due to the crushing of particles and the energy of compaction. Finally, this paper provides ideas that improve the understanding of the variables that lead to high or low CBR values for fine and granular materials.
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