Implementation of an Advanced Constitutive Models for Fine-Grained Soils

This article presents the effect of silt proportion on the hypoplastic parameters (exponent n, granular hardness hs, exponent a, and exponent beta) used for numerical simulation, calculation of emax, and transitional fines content (Fct). Fifteen oedometer tests were carried out at various relative densities (RD = 30, 65, and 80%) to evaluate their effect on the compressibility parameters such as compression index Cc, secant oedometer modulus E-secant, and pre-consolidation pressure sigma'p. Additionally, ten monotonic undrained triaxial tests were conducted at RD = 65% and RD = 80% to determine the value of the a parameter used in numerical simulation. The results obtained indicate that that the void ratio decreases with the increasing proportion of fine fraction up to 30% and further decreases with an additional increase of fines up to 40% for the three cases of relative densities (RD = 30, 65 and 80%). Additionally, it is shown from our results that the hypoplastic model is able to simulate soil behavior under undrained and oeodometer conditions. It was found that an increase in the a parameter leads to an increase in the dilatancy of the curves observed in the triaxial test. On the other hand, the parameters a and beta seem to have no effect on the compressibility curves, and it was necessary to rely on their physical parameters. The transitional fines content (F-ct) F-Ct F-Ct depends on the stress level and maximum void ratio, which are calculated from the parameters of the hypoplastic model (eio, hs, ps, n).