Estimating elastic modulus of California bearing ratio test sample using finite element model

Abstract

Numerical simulation of California bearing ratio (CBR) test needs a set of soil parameters including elastic modulus, Poisson’s ratio, stiffness parameters and strength parameters corresponding to soil model. Misestimating of these parameters ends up the simulation into erroneous output. The elastic modulus of soil contained in the CBR mould is difficult to measure due to the mechanics involved in it during test. Present study attempted to estimate the elastic modulus of CBR soil sample based on finite element model (FEM). Plaxis 2D program was used to model CBR test. Parameters involved in the modelling were elastic modulus, Poisson’s ratio and shear strength parameters. CBR test and direct shear test were carried in the laboratory for the test soil. Using the regression model and laboratory test results, elastic modulus of the test soil sample was calculated. The validation of the regression and CBR model was carried out by comparing the results of simulation and laboratory test. Coefficient of determination (R2) of the plot between the results of laboratory test and output of CBR model was found 0.99, which shows the acceptance of elastic modulus for further numerical analysis of the CBR test.