Application of an anisotropic hardening model in the analysis of elasto–plastic deformation of soils

Abstract

This Paper extends the previous work (Mróz, Norris and Zienkiewicz, 1978a) where an anisotropic hardening model for soils was proposed, taking into account both isotropic hardening due to porosity changes and anisotropy effects induced by the initial consolidation process. The analysis is restricted to the case of triaxial state for which two principal stresses are equal. The incremental relations are derived and applied to study the drained and undrained material behaviour after isotropic and anisotropic K0 consolidation of clays. The material response under cyclic loading is also discussed. The predicted inelastic behaviour is compared with available experimental results for kaolin and Weald clays for which the material parameters are also identified. Further improvements of the model are indicated, Cette étude prolonge le travail antérieur (Mróz, 1978a) réalisé par Norris et Zienkiewicz dans lequel un modèle anisotrope de durcissement pour sols était proposé, tenant compte du durcissement isotrope par suite de changements de porosité ainsi que les effets induits par le procédé de consolidation instantanée. L'analyse est limitée au cas de l'étreinte triaxiale dans laquelle deux contraintes principales sont égales. Les relations incrémentales sont dérivées et appliquées à l'étude du comportement de la matière drainée et non drainée après la consolidation K0 isotrope et anisotrope des argiles. Le comportement de la matière sous chargement cyclique est aussi examiné. Le comportement non élastique prédit, est comparé aux résultats expérimentaux obtenus sur le kaolin et les argiles de Weald pour lesquels les paramètres de matière sont aussi identifiés. D'autres améliorations du modèle sont indiquées.

The application of a three-surface kinematic hardening model to repeated loading of thinly surfaced pavements

“…This two-surface bubble model is similar to the models described by Mróz et al (1979) and Hashiguchi (1985). A small inner true yield surface, which bounds a small truly elastic region, was introduced − see Figure 2.14.…”

“…Iwan (1967) andMróz (1967) independently formulated the first kinematic hardening model for metals which was later applied to soils by Prévost (1977Prévost ( , 1978. Mróz et al (1979) described a two-surface kinematic hardening model which has a kinematic yield surface inside the consolidation surface. If the current stress state reaches the yield surface, plastic deformations occur and the yield surface translates.…”

“…If the current stress state reaches the yield surface, plastic deformations occur and the yield surface translates. Hashiguchi (1985) described a model which is similar to the model described by Mróz et al (1979) and introduced an extra surface in order to obtain a smooth stress-strain curve beyond yield. Hashiguchi (1993) also describes in detail how the kinematic hardening concept may be applied to generate multi-surface and infinite surface models.…”

“…The translation laws used to control the movement of the kinematic surfaces have the same form as those used in the two-surface model developed by Mróz et al (1979) and Al-Tabbaa (1987). These translation laws follow a rule which states that the centre of a surface should always move along a vector joining the current stress state to its conjugate point on the next surface, as shown in The conjugate point corresponding to the current stress state can be calculated using the following equation:…”

Diffuse bifurcations engraving diverse shear bands in granular materials

“…The stress updating algorithm based on the return-mapping scheme and the algorithmic (consistent) elastoplastic tangent moduli tensor † Unconventional plasticity models include the nested multisurface model, [12][13][14] the two-surface model, [15][16][17][18] the infinite-surface model, 19 and the bounding surface model, 20,21 as well as the subloading surface model. 22,23 ‡ Soil behaviors successfully reproduced by the subloading surface Cam-clay model include a mechanical response of hardening accompanied by volumetric contraction typically observed in normally consolidated clays and loose sands, as well as typical behaviors of over-consolidated clays and dense sands exhibiting a smooth transition from initial volume contraction to dilation with hardening before a peak stress, followed by further dilation along with softening.…”