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- Alawaji, H., et al.
(författare)
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Implicit integration in soil plasticity under mixed control for drained and undrained response
- 1992
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Ingår i: International Journal for Numerical and Analytical Methods in Geomechanics. - : Wiley. - 0363-9061 .- 1096-9853. ; 16:10, s. 737-756
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Tidskriftsartikel (refereegranskat)abstract
- An algorithm is outlined for the implicit integration of isotropic plasticity models for an arbitrary choice of mixed stress and strain control variables. Drained as well as undrained behaviour is considered. The closest-point-projection method in conjunction with a completely strain-driven format is used in a core algorithm. In the drained case strain response variables are determined via iterations to satisfy equilibrium of prescribed and calculated stresses that correspond to the strain response variables. In the undrained case, on the other hand, strains and pore pressure are determined via simultaneous iterations to satisfy equilibrium and the incompressibility condition. The algorithm is applied to a new generalized cam-clay model, and various iteration techniques are assessed. In particular, Newton iterations which employ the matrix of algorithmic tangent stiffness moduli are shown to compete favourably with more conventional methods.
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| 7. |
- Axelsson, Kennet, et al.
(författare)
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Characteristics and integration of undrained response of silty soils
- 1989
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Ingår i: Numerical models in geomechanics. - London : Elsevier. - 1851663460 ; , s. 195-203
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Konferensbidrag (refereegranskat)abstract
- Constitutive behaviour of silt is discussed with emphasis on undrained response. Triaxial undrained tests performed on silt shows contractant behaviour at small strains but dilatant behaviour at higher strains, whereafter the soil fails. A constitutive model for silt based on elastoplacticity is proposed and numerically investigated
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| 8. |
- Axelsson, Kennet, et al.
(författare)
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Constitutive modelling of Swedish fine grained soils
- 1991
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Ingår i: Deformation of soils and displacements of structures. - : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9054100028 ; , s. 183-187
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Konferensbidrag (refereegranskat)
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| 9. |
- Axelsson, Kennet
(författare)
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Constitutive properties and modelling of silty soils
- 1989
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Ingår i: Proceedings of the twelfth International Conference on Soil Mechanics and Foundation Engineering = Comptes Rendus du Douzième Congrès International de mécanique des Sols et des Travaux de Fondations / Vol. 1. - Rotterdam : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 906191891X ; , s. 687-690
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Konferensbidrag (refereegranskat)abstract
- brief description of the characteristics of silty soils is presented. Results are given from undrained triaxial tests on Swedish silts, which show contractant behaviour at small strains whereas the behaviour becomes dilatant close to the critical state. The undrained effective stress path then changes direction at the critical state line which will be followed while the shear strain increases. A simple constitutive model was adopted to predict the transitional behaviour. The model, which is based on the Cam-Clay concept, includes shear hardening in addition to volumetric hardening. Comparisons of predicted and experimental results in the undrained case show a very good agreement, in particular with respect to the transitional behaviour represented by a ``hook'' in the effective stress path.
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| 10. |
- Axelsson, Kennet, et al.
(författare)
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Determination of constitutive parameters for soils based on optimization
- 1991
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Ingår i: Computer methods and advances in geomechanics. - Rotterdam : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9061911893 ; , s. 569-574
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Konferensbidrag (refereegranskat)abstract
- Optimization-based methods for the determination of constitutive parameters of material models are evaluated. Rosenbrock's and Levenberg-Marquardt's algorithms are considered in particular. Based on experimental data for Swedish silt, two plasticity models are calibrated and their performances are compared
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