A viscoplastic SANICLAY model for natural soft soils

Abstract

This paper focuses on constitutive and numerical modeling of strain-rate dependency in natural clays while also accounting for anisotropy and destructuration. For this purpose the SANICLAY model that accounts for the fabric anisotropy with the additional destructuration feature that accounts for sensitivity of natural clays, is considered as the reference model. An associated flow rule is adopted for simplicity. The model formulation is refined to also account for the important feature of strain-rate dependency using the Perzyna’s overstress theory. The model is then implicitly integrated in finite element program PLAXIS. Performance of the developed and implemented model is explored by comparing the simulation results of several element tests and a boundary value problem to the available experimental data. The element tests include the constant strain-rate under one-dimensional and triaxial conditions on different clays. The boundary value problem includes a test embankment, namely embankment D constructed at Saint Alban, Quebec. For comparison, the test embankment is also analyzed using the Modified Cam-Clay (MCC) model, the SANICLAY model, and the viscoplastic model but without destructuration. Results demonstrate the success of the developed and implemented viscoplastic SANICLAY in reproducing the strain-rate dependent behavior of natural soft soils.