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Hypoplastic constitutive equation with internal variables
114A
PROPERTIES:DEFORMATION
algorithm has been implemented in the recently developed DEM code ELLIPSE3D. (from Authors) 963102 An indicrect boundary integral equation method for poroelasticity R. K. N. D. Rajapakse & T. Senjuntichai, International Journal for Numerical & Analytical nits, 19(9), 1995, pp 587-614.
Methods in Geomecha-
This paper presents an indirect boundary integral equation method for analysis of quasi-static, time-harmonic and transient boundary value problems related to infinite and semi-infinite poroelastic domains. The present analysis is based on Biot’s theory for poroelastodynamics with fluid viscous dissipation. (from Authors) 963103
Direct measurement of volume strain during experimental deformation of porous materials M. P. Olsen, M. T. Brandon & R. B. Gordon, International Journal of Rock Mechanics & Mining Sciences, 32(4), 1995, pp 371-373. Marone et al. used a servo-controlled pressure intensifier counled with an LVDT to record volume chances necessarv to &.intain a constant pore pressure within si&lated fauit gouge in a shearing apparatus. Volume strain can also be measured using radial strain gauges mounted directly on the specimen, but this approach only measures local changes in the radial section of the deforming sample. A new system for the measurement of changes in pore volume in porous materials is introduced (from Authors) 963104 Plane-strain instability of saturated porous media J. P. Bardet & A. Shiv, Journal of Engineering Mechanics ASCE, 121(6), 1995, pp 717-724. This paper investigates the plane-strain instability of rectangular blocks that are made of porous materials saturated with a fluid. The material behavior is modelled with rate-type constitutive equations, and the instability generated by the interaction of nearly incompressible solid and fluid constituents is studied. Elastoplastic models are found to undergo two-phase instability even though the solid phase remains stable. Two-phase instability is more likely to occur in contractant hardening materials than in dilatant materials. Its emergence is triggered by the solid-fluid interaction, and is delayed by the grain-fluid compressibility. Two-phase instability also takes place in dilatant materials, but is less catastrophic than in contractant materials. (from Authors) 963105 On a tbreedimensional anisotropic plasticity model for soil R. S. Crouch & J. P. Wolf, Geotechnique, 45(2), 1995, pp 301-305. The unified three-dimensional critical state bounding-surface plasticity model for soil (gUTS) incorporates an anisotropic bounding surface by operating with a reduced deviatoric stress vector defined as the conventional deviatoric stress vector minus the dimensionless deviatoric vector {a} multiplied by the mean effective stress. Only when there is no Lode angle dependency will the deviatoric sections be geometrically similar and will the stress ratio corresponding to the critical state in the anisotropic case be the same as that in the isotropic case. If the effective stress ratio corresponding to the critical state depends on the reduced Lode angle, all deviatoric sections will remain geometrically similar for a given {a}, but the shapes of the sections will vary as {a} changes. These deviatoric sections generally become concave for large values of a. (Authors) 963106 Stress-dependency of elastic module for cross-anisotropic Soils
P. Dakoulas & S. Yu, Geotechnique, 45(2), 1995, pp 325-332.
& STRENGTH
Presents a general cross-anisotropic model for purely elastic behaviour based on five independent elastic parameters. In accordance with experimental evidence, the model assumes that the elastic Young’s moduli and shear moduli are functions of the stress state; the three Poisson’s ratios are practically constant. Moreover, the model assumes that, although Eh and E, increase with increasing confining stress, the ratio EdE, remains constant. This paper deals with the effects of non-linearity and anisotropy on the elastic soil response. (from Authors) 963107 Unsaturated strength bebaviour of compacted later& soils U. Mahalinga-Iyer & D. J. Williams, Geotechnique, 45(2), 1995, pp 317-320. Values obtained for Fredlund’s parameter +b for the two lateritic soils tested vary with suction. Values obtained for Toll’s parameters for the lateritic soils tested lie in the same range as his results for Kenya gravel. Suction has no effect on the shear strength of an unsaturated soil below a degree of saturation of 53-55%. (from Authors) 963108 Modified model of the nonlinear deformation of cohesive soil.9 S. S. Vyalov & Z. S. Shaaban, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 155-160; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 5, 1994, pp 2-6. A model is proposed for description of the elastoplastic deformation of soil; it is distinguished from existing models by simplicity and a limited number of parameters, as determined from standard tests. The model takes into account the soil’s nonlinearity, the existence of irrreversible deformations, the structural strength of the soil, etc. (Journal summary) 963109 Modeling and testing of cohesive soil using distnrbed+tate concept D. R. Katti t C. S. Desai, Journal of Engineering Mechanics - AXE, 121(5), 1995, pp 648-658. A new constitutive model for predicting the undrained stressdeformation and power water pressure response of saturated cohesive soils subjected to cyclic loading is developed using the disturbed-state concept @SC). The model takes into account inelastic response during loading (virgin) and unloading-reloading (nonvirgin) behavior. Comprehensive laboratory tests have been performed on undisturbed soft (marine) clay samples. Overall, the proposed model provides highly satisfactory predictions of the observed behavior during virgin and non-virgin loading. (from Authors) 963110 Stiffness of fine-grained soil at very small strains G9yigani &J. H. Atkinson, Geotechnique, 45(2), 1995, pp The stiffness of soil of very small strain Go is a useful parameter for characterizing the non-linear stress-strain behaviour of soil for monotonic loading. Tests were carried out on tine-grained soils in a hydraulic triaxial cell fitted with bender elements and with local axial gauges. From the results of these tests simple expressions were obtained which describe the variation of Go with current state in terms of the current stress and overconsolidation ratio. The parameters in these expressions were found to depend on plasticity index. The simple expressions for GO were found to apply generally at larger strains, with the values for the parameters also depending on the current strain. (from Authors) 963111 Hypoplastic constitutive equation with internal variables D. Kolvmbas. I. Herle UCP. A. Von Wolfersdorff. Znternational journal for Numerical & Analytical Geomechanics, 19(6), 1995, pp 415-436.
Methods
in
PROPERTIES:DEFORMATION
algorithm has been implemented in the recently developed DEM code ELLIPSE3D. (from Authors) 963102 An indicrect boundary integral equation method for poroelasticity R. K. N. D. Rajapakse & T. Senjuntichai, International Journal for Numerical & Analytical nits, 19(9), 1995, pp 587-614.
Methods in Geomecha-
This paper presents an indirect boundary integral equation method for analysis of quasi-static, time-harmonic and transient boundary value problems related to infinite and semi-infinite poroelastic domains. The present analysis is based on Biot’s theory for poroelastodynamics with fluid viscous dissipation. (from Authors) 963103
Direct measurement of volume strain during experimental deformation of porous materials M. P. Olsen, M. T. Brandon & R. B. Gordon, International Journal of Rock Mechanics & Mining Sciences, 32(4), 1995, pp 371-373. Marone et al. used a servo-controlled pressure intensifier counled with an LVDT to record volume chances necessarv to &.intain a constant pore pressure within si&lated fauit gouge in a shearing apparatus. Volume strain can also be measured using radial strain gauges mounted directly on the specimen, but this approach only measures local changes in the radial section of the deforming sample. A new system for the measurement of changes in pore volume in porous materials is introduced (from Authors) 963104 Plane-strain instability of saturated porous media J. P. Bardet & A. Shiv, Journal of Engineering Mechanics ASCE, 121(6), 1995, pp 717-724. This paper investigates the plane-strain instability of rectangular blocks that are made of porous materials saturated with a fluid. The material behavior is modelled with rate-type constitutive equations, and the instability generated by the interaction of nearly incompressible solid and fluid constituents is studied. Elastoplastic models are found to undergo two-phase instability even though the solid phase remains stable. Two-phase instability is more likely to occur in contractant hardening materials than in dilatant materials. Its emergence is triggered by the solid-fluid interaction, and is delayed by the grain-fluid compressibility. Two-phase instability also takes place in dilatant materials, but is less catastrophic than in contractant materials. (from Authors) 963105 On a tbreedimensional anisotropic plasticity model for soil R. S. Crouch & J. P. Wolf, Geotechnique, 45(2), 1995, pp 301-305. The unified three-dimensional critical state bounding-surface plasticity model for soil (gUTS) incorporates an anisotropic bounding surface by operating with a reduced deviatoric stress vector defined as the conventional deviatoric stress vector minus the dimensionless deviatoric vector {a} multiplied by the mean effective stress. Only when there is no Lode angle dependency will the deviatoric sections be geometrically similar and will the stress ratio corresponding to the critical state in the anisotropic case be the same as that in the isotropic case. If the effective stress ratio corresponding to the critical state depends on the reduced Lode angle, all deviatoric sections will remain geometrically similar for a given {a}, but the shapes of the sections will vary as {a} changes. These deviatoric sections generally become concave for large values of a. (Authors) 963106 Stress-dependency of elastic module for cross-anisotropic Soils
P. Dakoulas & S. Yu, Geotechnique, 45(2), 1995, pp 325-332.
& STRENGTH
Presents a general cross-anisotropic model for purely elastic behaviour based on five independent elastic parameters. In accordance with experimental evidence, the model assumes that the elastic Young’s moduli and shear moduli are functions of the stress state; the three Poisson’s ratios are practically constant. Moreover, the model assumes that, although Eh and E, increase with increasing confining stress, the ratio EdE, remains constant. This paper deals with the effects of non-linearity and anisotropy on the elastic soil response. (from Authors) 963107 Unsaturated strength bebaviour of compacted later& soils U. Mahalinga-Iyer & D. J. Williams, Geotechnique, 45(2), 1995, pp 317-320. Values obtained for Fredlund’s parameter +b for the two lateritic soils tested vary with suction. Values obtained for Toll’s parameters for the lateritic soils tested lie in the same range as his results for Kenya gravel. Suction has no effect on the shear strength of an unsaturated soil below a degree of saturation of 53-55%. (from Authors) 963108 Modified model of the nonlinear deformation of cohesive soil.9 S. S. Vyalov & Z. S. Shaaban, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 155-160; translated from: Osnovaniya, Fundamenty i Mekhanika Gruntov, 5, 1994, pp 2-6. A model is proposed for description of the elastoplastic deformation of soil; it is distinguished from existing models by simplicity and a limited number of parameters, as determined from standard tests. The model takes into account the soil’s nonlinearity, the existence of irrreversible deformations, the structural strength of the soil, etc. (Journal summary) 963109 Modeling and testing of cohesive soil using distnrbed+tate concept D. R. Katti t C. S. Desai, Journal of Engineering Mechanics - AXE, 121(5), 1995, pp 648-658. A new constitutive model for predicting the undrained stressdeformation and power water pressure response of saturated cohesive soils subjected to cyclic loading is developed using the disturbed-state concept @SC). The model takes into account inelastic response during loading (virgin) and unloading-reloading (nonvirgin) behavior. Comprehensive laboratory tests have been performed on undisturbed soft (marine) clay samples. Overall, the proposed model provides highly satisfactory predictions of the observed behavior during virgin and non-virgin loading. (from Authors) 963110 Stiffness of fine-grained soil at very small strains G9yigani &J. H. Atkinson, Geotechnique, 45(2), 1995, pp The stiffness of soil of very small strain Go is a useful parameter for characterizing the non-linear stress-strain behaviour of soil for monotonic loading. Tests were carried out on tine-grained soils in a hydraulic triaxial cell fitted with bender elements and with local axial gauges. From the results of these tests simple expressions were obtained which describe the variation of Go with current state in terms of the current stress and overconsolidation ratio. The parameters in these expressions were found to depend on plasticity index. The simple expressions for GO were found to apply generally at larger strains, with the values for the parameters also depending on the current strain. (from Authors) 963111 Hypoplastic constitutive equation with internal variables D. Kolvmbas. I. Herle UCP. A. Von Wolfersdorff. Znternational journal for Numerical & Analytical Geomechanics, 19(6), 1995, pp 415-436.
Methods
in