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Rheological behaviour of a contact layer - field measurements, constitutive modelling and back analysis by FEM
214A 914117 Application of acoustic emission parameters as a criterion of stress-strain behaviour of rocks Krayewska-Pininska, J: Karska, Z Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 VI. P413-417. Publ Rotterdam. A ,4 Balkema. 1990 Eleven types of inhomogeneous rock were tested to failure in uniaxial compression: diabase (intact, disturbed, fractured), slate (intact, fractured, re-cemented), breccia, and sandstone (thin bedded and cracked, laminated, compact, porous and thick bedded). Sonic, ultrasonic, and total acoustic emission and P wave attenuation were monitored during the tests. Effects of lithology on acoustic emission are discussed. Three phases of acoustic emission are found, the last, occurring with specific frequency at about 80% of critical stress, being a potential failure precursor.
Time dependent behaviour See also." 914441. 914471 914118 Test of the generalized theory of visco-elasticity in London Clay. Technical note Abbiss, C P; Lewin, P I Geotechnique 1/40, N4, Dec 1990. P641-646
Generalised viscoelastic theory allows creep rate to be related to the quality factor Q, which is defined in terms of energy loss during hysteresis and can be determined from comparisons of pulse and steady state wave velocities in situ. The validity of the relation under conditions which will be found beneath foundations has been tested in the laboratory using a cubic cell. The creep rate defined can be used for class A settlement calculations, those not considering change of soil modulus with time and deformatioia. 914119 Modeling the consolidation of a porous aggregate of dry salt as isostatic hot pressing Holcomb, D J; Zeuch, D H J Geophys Res 1/95, NBIO, Sept 1990, PI5611-15622 Data on time dependent and instantaneous consolidation of dry granular salt were obtained at temperatures 21-100 dug C, hydrostatic pressure 1.7-21MPa, and times to 100 hours. A model of isostatic hot pressing is used to interpret the results. If a term to account for brittle consolidation (particle rearrangement and fracturing) is included, most of the observed behaviour can be predicted. Absolute density is underpredicted if this term is omitted. As the model uses creep mechanisms known to apply in laboratory and geological conditions, those results can be extrapolated to times beyond laboratory feasibility.
predicted are within an order of magnitude of" those measured and for which microstructural evidence suggests dislocation climb is the controlling mechanism. 914121 Thermoplasticity of saturated soils and shales: constitutive equations Hueckel, T; Borsetto, M J Geotech Engng D& ASCE Vl16, NI2. Dec 1990, P17651777 A combination of critical state and thermoplasticity theories is used to formulate constitutive relations for soils under thermomechanical conditions. Strain hardening is via thermoplastic volumetric strain, to allow reference to Cam Clay type soil models. The most specific and sophisticated soil model available should be used to describe mechanical behaviour. Variation of elastic domain with temperature, consolidation, strain rate nonassociativity, and undrained failure due to heating can be described. 914122 Thermoplasticity of saturated clays: experimental constitutive study Hueckel, T; Baldi, G J Geotech Engng Div ASCE VII6, NI2. Dec 1990, P17781798 The previously published framework for thermoplastic behaviour of clays (Hueckel and Borsetto, 1990) is used to analyse experiments on natural Boom and Pasquasia clays and remoulded Pontida clay over the temperature range 18-115 dug C. Isothermal mechanical loading tests at different temperatures and heating/cooling tests at different constant mechanical loads were used. The proposed model predicts reasonably well thermoplastic consolidation, undrained failure during heating, thermally increasing ductility in triaxial compression, and cyclic undrained heating and cooling. 914123 Rheological behaviour of a contact layer - field measurements, constitutive modelling and back analysis by FEM Dolezalova, M; Herle, V Proc International Symposium on Rock Joints, Loen, 4-6 June 1990 P617-625. Publ Rotterdam." A A Balkema, 1990 Sliding of slope debris deposits along the contact with underlying clay at the Jezerka open pit coal mine, Czechoslovakia, has prompted study of the behaviour of the interface. Laboratory tests were carried out on interface samples retrieved from boreholes in order to characterise mechanical parameters. Finite element back analysis of field observations confirmed these values. Predictions of slope movement, taking into account creep, are close to observed movement.
914120 Multicomponent diffusion and creep in olivine Jaoul, O J Geophys Res V95, N B l l . Oct 1990, P17631-17642
914124 Effect of drying-wetting on long term strength of mudstone Shinjo, T; Komiya, Y Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Jane&o, 13-18 August 1989 V1, P551-554. Publ Rotterdam." A A Balkema, 1989
Diffusion coefficients of the constituents of olivine are well documented for the temperature and oxygen partial pressure ranges which can be duplicated in the laboratory. Multicomponent diffusion theory is used as a basis for a model of diffusion creep of olivine, using these parameters. Creep rates
Drained creep tests were carried out on weathered and unweathered intact mudstone in various axial directions to clarify its long term behaviour and the effects of wet-dry weathering on creep strength. A method is developed to forecast long term strength of the anisotropic mudstone.
~, 1991 Pergamon Press plc. Reproduction not permitted
Time dependent behaviour See also." 914441. 914471 914118 Test of the generalized theory of visco-elasticity in London Clay. Technical note Abbiss, C P; Lewin, P I Geotechnique 1/40, N4, Dec 1990. P641-646
Generalised viscoelastic theory allows creep rate to be related to the quality factor Q, which is defined in terms of energy loss during hysteresis and can be determined from comparisons of pulse and steady state wave velocities in situ. The validity of the relation under conditions which will be found beneath foundations has been tested in the laboratory using a cubic cell. The creep rate defined can be used for class A settlement calculations, those not considering change of soil modulus with time and deformatioia. 914119 Modeling the consolidation of a porous aggregate of dry salt as isostatic hot pressing Holcomb, D J; Zeuch, D H J Geophys Res 1/95, NBIO, Sept 1990, PI5611-15622 Data on time dependent and instantaneous consolidation of dry granular salt were obtained at temperatures 21-100 dug C, hydrostatic pressure 1.7-21MPa, and times to 100 hours. A model of isostatic hot pressing is used to interpret the results. If a term to account for brittle consolidation (particle rearrangement and fracturing) is included, most of the observed behaviour can be predicted. Absolute density is underpredicted if this term is omitted. As the model uses creep mechanisms known to apply in laboratory and geological conditions, those results can be extrapolated to times beyond laboratory feasibility.
predicted are within an order of magnitude of" those measured and for which microstructural evidence suggests dislocation climb is the controlling mechanism. 914121 Thermoplasticity of saturated soils and shales: constitutive equations Hueckel, T; Borsetto, M J Geotech Engng D& ASCE Vl16, NI2. Dec 1990, P17651777 A combination of critical state and thermoplasticity theories is used to formulate constitutive relations for soils under thermomechanical conditions. Strain hardening is via thermoplastic volumetric strain, to allow reference to Cam Clay type soil models. The most specific and sophisticated soil model available should be used to describe mechanical behaviour. Variation of elastic domain with temperature, consolidation, strain rate nonassociativity, and undrained failure due to heating can be described. 914122 Thermoplasticity of saturated clays: experimental constitutive study Hueckel, T; Baldi, G J Geotech Engng Div ASCE VII6, NI2. Dec 1990, P17781798 The previously published framework for thermoplastic behaviour of clays (Hueckel and Borsetto, 1990) is used to analyse experiments on natural Boom and Pasquasia clays and remoulded Pontida clay over the temperature range 18-115 dug C. Isothermal mechanical loading tests at different temperatures and heating/cooling tests at different constant mechanical loads were used. The proposed model predicts reasonably well thermoplastic consolidation, undrained failure during heating, thermally increasing ductility in triaxial compression, and cyclic undrained heating and cooling. 914123 Rheological behaviour of a contact layer - field measurements, constitutive modelling and back analysis by FEM Dolezalova, M; Herle, V Proc International Symposium on Rock Joints, Loen, 4-6 June 1990 P617-625. Publ Rotterdam." A A Balkema, 1990 Sliding of slope debris deposits along the contact with underlying clay at the Jezerka open pit coal mine, Czechoslovakia, has prompted study of the behaviour of the interface. Laboratory tests were carried out on interface samples retrieved from boreholes in order to characterise mechanical parameters. Finite element back analysis of field observations confirmed these values. Predictions of slope movement, taking into account creep, are close to observed movement.
914120 Multicomponent diffusion and creep in olivine Jaoul, O J Geophys Res V95, N B l l . Oct 1990, P17631-17642
914124 Effect of drying-wetting on long term strength of mudstone Shinjo, T; Komiya, Y Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Jane&o, 13-18 August 1989 V1, P551-554. Publ Rotterdam." A A Balkema, 1989
Diffusion coefficients of the constituents of olivine are well documented for the temperature and oxygen partial pressure ranges which can be duplicated in the laboratory. Multicomponent diffusion theory is used as a basis for a model of diffusion creep of olivine, using these parameters. Creep rates
Drained creep tests were carried out on weathered and unweathered intact mudstone in various axial directions to clarify its long term behaviour and the effects of wet-dry weathering on creep strength. A method is developed to forecast long term strength of the anisotropic mudstone.
~, 1991 Pergamon Press plc. Reproduction not permitted