Elastoplastic modeling of sand-silt mixtures

Experimental observations have shown that the mechanical behavior of sand-silt mixtures is highly dependent on the proportions of sand and silt. Our present paper proposes a simple elastoplastic model for the stress-strain behavior of sand-silt mixtures. The inter-grain contact index is firstly reviewed. A formulation which links the inter-grain contact index with the void ratio is then proposed and validated by measuring the index void ratios of various sand-silt mixtures. The formulation is applied to determine the position of the critical state line of sand-silt mixtures from sand to silt. Based on this formulation, a simple elastoplastic model is then developed. The model parameters can be easily determined from conventional triaxial tests and measurements of the index void ratios. The predictive capability of the model was examined by comparing the simulations and the experimental results of undrained triaxial tests on Foundry and Ottawa sand-silt mixtures from sand to silt.