A viscoplastic subloading soil model for rate‐dependent cyclic anisotropic structured behaviour

Abstract

Summary This paper presents a new purely viscoplastic soil model based on the subloading surface concept with a mobile centre of homothety, enabling the occurrence of viscoplastic strains inside the yield surface and avoiding the abrupt change in stiffness of the traditional overstress viscoplastic models. This is required for overconsolidated soils. The model is formulated to reproduce the soil rate‐dependent behaviour under cyclic loading (changes in loading direction) and incorporates both initial and induced anisotropy, as well as destructuring. The model shows good qualitative response to some imposed three‐dimensional stress paths under quasi‐inviscid (elastoplastic) behaviour. Some of the main time‐dependent aspects of soil behaviour that the model is capable of reproducing were also illustrated. The capability of the model to adequately reproduce the results from an undrained triaxial test performed on stiff overconsolidated clays from the Lisbon region (Formação de Benfica), with an unloading–reloading deviatoric stress cycle at constant mean stress, that incorporates a series of staggered fast loading and creep stages, was evaluated. The model was able to reproduce well the main observed aspects of the time‐dependent stress–strain response and pore pressure evolution of a stiff overconsolidated clay under complex loading. The revised and generalised viscoplastic subloading surface concept is viable and can be applied to a consistent extension to viscoplasticity, including in the interior of the yield surface, of existing elastoplastic models formulated for soils and other materials. Copyright © 2016 John Wiley & Sons, Ltd.

Reviewing the Modeling Aspects and Practices of Shallow Geothermal Energy Systems

“…The subloading concept due to Hashiguchi [182] was also used to reproduce the influence of non-isothermal conditions on the stress-strain-time behavior of soils. A version of the viscoplastic subloading soil model proposed in Maranha et al [184], restricted to isotropic stress and strain conditions, was extended to non-isothermal conditions in [184], introducing temperature dependence of the size of the yield surface and of the viscosity. This model was able to capture well the large expansion volumetric strains observed in highly over-consolidated clays in the initial stages on heating tests [185].…”

Integration schemes with substepping algorithms for creep analysis in geomaterials

“…In the basic formulation of the soft soil creep model, 11 parameters are necessary. More details about this creep model and more advanced ones for soft and frozen soils can be found in previous studies …”

“…More details about this creep model and more advanced ones for soft and frozen soils can be found in previous studies. [1][2][3][4][22][23][24]…”

“…From a material or local point of view, different constitutive models based on creep laws have been proposed for geotechnical applications in soft and frozen soils [1][2][3][4][22][23][24] as well as for geomechanical applications in salt rocks. 6,7,[10][11][12]14,25 Those models provide relationships to determine creep rates dependent on stress, temperature, and time.…”

Numerical simulations of the reuse of piled raft foundations in clay

“…More theoretical formulations were later documented by Sekiguchi [43], Adachi and Oka [1], and Borja and Kavazanjian [7]. Highly advanced constitutive models have recently been developed to capture various soil characteristics including soil destructuration, anisotropy (due to deposition history) and cyclic loading [19,20,24,26,31,34,35,41,49,55,57,59,61]. This is not intended to be an exhaustive list, however, and more in-depth discussion on this topic is available in Liingaard et al [33].…”