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Implementation of modern constitutive laws and analysis of field problems
300A
method is presented, then a comprehensive review of hierarchical single surface constitutive models. Finally, the implementation of these models in nonlinear finite element procedures for solution of practical and realistic boundary value problems is illustrated, including footings in sand, cyclic loading of piles in clay, dynamic response of foundations,anchors in sand, and three dimensional seepage. 113 refs.
915273 Mechanics of partially saturated media Schrefler, B A; Simoni, L; Xikui, L; Zienkiewicz, 0 C In: Numerical Metho& and Constitutive Mo&&g in Geomechanics (Znternational Centre for Mechanical Sciences, Courses and Lectures - No 311) P169-209. Pub1 Wien: Springer- Verlag, 1990
Governing equations for the mechanics of multicomponent continua, in the case of partially saturated soils, are derived using an averaging technique. Mass balance and linear momentum balance equations of the constituents and the whole mixture are obtained for quasi static conditions and interactions between the phases taken into account. A finite element discretisation of the governing equations is finally presented.
915274 Implementation of modern constitutive laws and analysis of iield problems
Smith, I M In: Numerical Methodr and Constitutive MoaWing in Geomechanics (Znternatioaal Centre forMechanical Sciences, Courses and Lectures - No 311) P237-275. Pub1 Wien: Springer- Verlag, I990
915276 Numerical analysis for the interpretation of field measureme& in geomechanics
Sakurai, S In: Numerical Methods and Constitutive Mot&Z&g in Geomechanics (International Centre for Mechanical Sciences, Courses and Lectures - No 311) P35I-407. Pub1 Wien: Springer- Verlag, 1990
Because of the inherent inhomogeneity of geological materials, their behaviour often differs from that predicted. To overcome this drawback, the monitoring of structures during their excavation and re-evaluation of input data used in the design process are widely adopted. Back analysis procedures are reviewed and discussed. Case histories are presented considering excavation of tunnels in close proximity, determination of initial stress in a rock mass, plastic zone size and shape around an underground opening, nonlinear behaviour of rocks and soils, and cut slopes. The formulations presented are suitable for continuous or pseudo-continuous media. 915277 Numerical analysis of oil sand under nonisothermal conditions
Vaziri, H H; Byrne, P M Can Geotech J V27, N6, Dee 1990. P802-812 Theoretical equations are derived in terms of elastic and thermal properties of multiphase soil systems for changes in pore fluid pressure and soil stress under undrained and drained conditions respectively. These are linked to Biot’s generalised flow and deformation formulation in a form suitable for finite element implementation. A thermoconsolidation numerical model is developed using a modified hyperbolic stress strain relation which can account for shear induced dilation. The model is verified under drained conditions and used to simulate various triaxial experiments on Athabasca oil sands. Dilatancy effects are important, particularly under undrained conditions. Some difficult to measure soil parameters can be determined by numerical analysis of laboratory tests. 915278
Complex geotechnical engineering problems require application of nonlinear material models in their solutions. The ultimate limit state of the works and likely deformations under normal loading conditions are parameters which should be available. A variety of constitutive laws of different complexity is described. Application to analysis of excavations in undrained clay, reinforced earth retaining walls, and foundations is illustrated.
915275 Numerical modelling of tunnels Swoboda, G In: Numerical Methods and Constitutive Moa’elbtg in Geomechanics (International Centre for Mechanical Sciences, Courses and Lectures - No 311) P277-318. Pub1 Wien: Springer- Verlag, 1990
Numerical analysis is now widely applied in tunnel design. Two dimensional modelling is first discussed. Loading conditions including stress redistribution due to excavation and effects of water pressure are first considered. Modelling of jointed rocks is examined in detail, with the decoupled finite element technique and damage tensor theory described. Three dimensional models, essential for cases where tunnel face effects cannot be dismissed, are discussed and described. 0
Complex stress paths and validation of constitutive models
Bianchini, G; Saada, A; Puccini, P; Lanier, J; Zitouni, Z Geotech Test J V14. NI. March 1991. P13-25 Realistic constitutive equations and failure criteria are essential to solution of complex soil mechanics problems. The predictive capacity of current soil models for granular cohesionless soils has been analysed using results of hollow cylinder and true triaxial (cube) tests carried out at Case Westem Reserve and Grenoble Universities. Effects of different boundary conditions induced by the equipment on results are highlighted. The predictive capacities are evaluated and adequacy of the available models to predict simple and complicated stress paths using results from standard tests is discussed. 915279 Endochronic plasticity theory with shear-volumetric coupling
Valanis, K C; Peters, J F Znt J Num Anal Meth Geomech Vl5, N2. Feb 1991. P77-102 The concept of endochronic plasticity, which deals with response of materials by means of memory integrals expressed in terms of fast-decaying functions, is used to derive from thermodynamic principles a constitutive equation for dilatant soils. Three separate models are proposed, of which one is selected on the basis of analytical simplicity and plausibility of its thermodynamics and physical foundations. It is used to model the dilatant behaviour of sand, and results are compared to experiment.
1991 Pergamon Press plc. Reproduction
not permitted
method is presented, then a comprehensive review of hierarchical single surface constitutive models. Finally, the implementation of these models in nonlinear finite element procedures for solution of practical and realistic boundary value problems is illustrated, including footings in sand, cyclic loading of piles in clay, dynamic response of foundations,anchors in sand, and three dimensional seepage. 113 refs.
915273 Mechanics of partially saturated media Schrefler, B A; Simoni, L; Xikui, L; Zienkiewicz, 0 C In: Numerical Metho& and Constitutive Mo&&g in Geomechanics (Znternational Centre for Mechanical Sciences, Courses and Lectures - No 311) P169-209. Pub1 Wien: Springer- Verlag, 1990
Governing equations for the mechanics of multicomponent continua, in the case of partially saturated soils, are derived using an averaging technique. Mass balance and linear momentum balance equations of the constituents and the whole mixture are obtained for quasi static conditions and interactions between the phases taken into account. A finite element discretisation of the governing equations is finally presented.
915274 Implementation of modern constitutive laws and analysis of iield problems
Smith, I M In: Numerical Methodr and Constitutive MoaWing in Geomechanics (Znternatioaal Centre forMechanical Sciences, Courses and Lectures - No 311) P237-275. Pub1 Wien: Springer- Verlag, I990
915276 Numerical analysis for the interpretation of field measureme& in geomechanics
Sakurai, S In: Numerical Methods and Constitutive Mot&Z&g in Geomechanics (International Centre for Mechanical Sciences, Courses and Lectures - No 311) P35I-407. Pub1 Wien: Springer- Verlag, 1990
Because of the inherent inhomogeneity of geological materials, their behaviour often differs from that predicted. To overcome this drawback, the monitoring of structures during their excavation and re-evaluation of input data used in the design process are widely adopted. Back analysis procedures are reviewed and discussed. Case histories are presented considering excavation of tunnels in close proximity, determination of initial stress in a rock mass, plastic zone size and shape around an underground opening, nonlinear behaviour of rocks and soils, and cut slopes. The formulations presented are suitable for continuous or pseudo-continuous media. 915277 Numerical analysis of oil sand under nonisothermal conditions
Vaziri, H H; Byrne, P M Can Geotech J V27, N6, Dee 1990. P802-812 Theoretical equations are derived in terms of elastic and thermal properties of multiphase soil systems for changes in pore fluid pressure and soil stress under undrained and drained conditions respectively. These are linked to Biot’s generalised flow and deformation formulation in a form suitable for finite element implementation. A thermoconsolidation numerical model is developed using a modified hyperbolic stress strain relation which can account for shear induced dilation. The model is verified under drained conditions and used to simulate various triaxial experiments on Athabasca oil sands. Dilatancy effects are important, particularly under undrained conditions. Some difficult to measure soil parameters can be determined by numerical analysis of laboratory tests. 915278
Complex geotechnical engineering problems require application of nonlinear material models in their solutions. The ultimate limit state of the works and likely deformations under normal loading conditions are parameters which should be available. A variety of constitutive laws of different complexity is described. Application to analysis of excavations in undrained clay, reinforced earth retaining walls, and foundations is illustrated.
915275 Numerical modelling of tunnels Swoboda, G In: Numerical Methods and Constitutive Moa’elbtg in Geomechanics (International Centre for Mechanical Sciences, Courses and Lectures - No 311) P277-318. Pub1 Wien: Springer- Verlag, 1990
Numerical analysis is now widely applied in tunnel design. Two dimensional modelling is first discussed. Loading conditions including stress redistribution due to excavation and effects of water pressure are first considered. Modelling of jointed rocks is examined in detail, with the decoupled finite element technique and damage tensor theory described. Three dimensional models, essential for cases where tunnel face effects cannot be dismissed, are discussed and described. 0
Complex stress paths and validation of constitutive models
Bianchini, G; Saada, A; Puccini, P; Lanier, J; Zitouni, Z Geotech Test J V14. NI. March 1991. P13-25 Realistic constitutive equations and failure criteria are essential to solution of complex soil mechanics problems. The predictive capacity of current soil models for granular cohesionless soils has been analysed using results of hollow cylinder and true triaxial (cube) tests carried out at Case Westem Reserve and Grenoble Universities. Effects of different boundary conditions induced by the equipment on results are highlighted. The predictive capacities are evaluated and adequacy of the available models to predict simple and complicated stress paths using results from standard tests is discussed. 915279 Endochronic plasticity theory with shear-volumetric coupling
Valanis, K C; Peters, J F Znt J Num Anal Meth Geomech Vl5, N2. Feb 1991. P77-102 The concept of endochronic plasticity, which deals with response of materials by means of memory integrals expressed in terms of fast-decaying functions, is used to derive from thermodynamic principles a constitutive equation for dilatant soils. Three separate models are proposed, of which one is selected on the basis of analytical simplicity and plausibility of its thermodynamics and physical foundations. It is used to model the dilatant behaviour of sand, and results are compared to experiment.
1991 Pergamon Press plc. Reproduction
not permitted