Modeling the cyclic degradation of clays with an anisotropic bounding surface plasticity model
Modeling the cyclic degradation of clays with an anisotropic bounding surface plasticity model
Clayey soils exhibit continuous stiffness degradation only for cyclic strain amplitudes exceeding a specific threshold, known as the degradation strain threshold. Similarly, the accumulation of strains due to degradation is observed only for cyclic stress ratios (CSRs) above a certain threshold. In this paper, we propose an advanced bounding surface (BS) rate-independent plasticity model for the cyclic response of clays, based on a previous version of the Simple Anisotropic CLAY (SANICLAY) plasticity model. Our proposed SANICLAY-BS model introduces an activation mechanism triggered by the amplitude of cyclic shear loading. We formulate this mechanism using a novel state variable that acts as a proxy for the applied cyclic stress. By introducing a threshold for this state variable, our model can simulate the degradation strain threshold and CSR threshold that characterize the undrained cyclic shear response of clayey soils. We demonstrate the model's performance against experimental data for different materials subjected to undrained cyclic shearing across a wide range of constant strain and stress amplitudes.
Francesca Palmieri; Mahdi Taiebat
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
1. Constitutive modelling for saturated and unsaturated soils
https://doi.org/10.53243/NUMGE2023-422
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