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Unconfined compression strength of soft aged clays
332A 906074 Experimental study of the localization of deformation on sand: influence of the mean stress (In French) Desrues, J; Hammad, W Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P31-32. Publ Rotterdam." A A Balkema, 1989
906078 Unconfined compression strength of soft aged clays Ohta, H; Nishihara, A; Iizuka, A; Morita, Y; Fukagawa, R; Arai, K Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P71-74. Publ Rotterdam." A A Balkema, 1989
Shear band formation for sands under biaxial stress was studied in the laboratory, with particular interest in the role of mean stress. A significant influence of confining stress on appearance of strain localization was seen. Increasing delay in strain localization with tendency to contractive behaviour was observed. The question of applicable deformation mechanisms for strain localization in contractive materials remains unanswered.
The use of UCS in stability analysis of soft aged clays is discussed considering residual effective stress in the so-called undisturbed samples. The method of Ohta (1983) was used to measure residual effective stress on clay samples from 22 sites across Japan. Interpretation of test results using an elastoplastic constitutive model leads to derivation of a correction factor to account for effects of sampling disturbance on UCS for use in conventional slip surface analysis. If this is applied, the UCS is in good agreement with values back calculated from failure analysis.
906O75 Gmax measured in oedometer and DSS tests using bender elements Dyvik, R; Olsen, T S Proc 12th International Conference on Soil Mechtmics and Foundation Engineering, Rio de Janoiro, 13-18 August 1989 V1, P39-42. Publ Rotterdam: A A Balkema, 1989
906079 Validation of failure models for granular soils Puccini, P; Saada, A; Bianchini, G Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P89-92. Publ Rotterdam: A A Balkema, 1989
Gmax was measured for Drammen clay, using piezoceramic bender elements mounted in oedometer, direct simple shear and triaxial devices. Results from the different tests at different levels of consolidation are compared. Gmax was easily and accurately determined using the DSS and oedometer devices, and values at comparable stages of consolidation are consistent. These results indicate the computational method and assumptions concerning shear wave travel in the bender elements are correct.
Over 250 hollow cylinder and true triaxial tests were carried out on three sands by Case Western Reserve and Grenoble universities. Test data were used to evaluate the Mohr Coulomb, William and Warnke, Lade, and Matsuoka and Akai failure criteria, and in development of a new tensor polynomial model. The Lade criterion is the most attractive for isotropic materials, the new model if anisotropy is taken into account.
906076 Strength and deformation of partly saturated soils Escario, V; Juca, J F T; Coppe, M S Proc 12th International Conference on Soil Mechanics and Foundation Engincering, Rio de Janeiro, 13-18 August 1989 VI, P43-46. Publ Rotterdam: A A Balkema, 1989
9O608O Versatile triaxial equipmentin the University of Oulu Ravaska, O; Kujala, K; Kallio, V Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P97-100. Publ Rotterdam: A A Balkema, 1989
Penetration and direct shear tests with controlled suction (up to 15MPa) were carried out on samples of two clays and a clayey sand. Factors affecting time to equilibrium are considered. Penetration tests indicate increase in deformation modulus and resistance with Suction, up to a maximum. Direct shear tests show similar behaviour, but with gentle decline once the maximum is reached. An elliptical relation is seen between shear strength and suction.
A conventional (Geonor K - I I ) triaxial cell has been automated and modified at the University of Oulu, Finland. It is capable of constant load and constant strain rate tests, and sensitive temperature control enables testing of frozen, freezing, and thawing soils. The cell design, control, and data acquisition are described. Some test results from shear and creep tests on frozen silt, and frost heave from a freezing test on glacial till are presented.
906077 General stress tests on granular materials Matsuoka, H; Suzuki, Y; Murata, T Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janciro, 13-18 August 1989 VI, P65-68. Publ Rotterdam: A A Balkema, 1989
906081 Quality assurance in laboratory testing Sallfors, D Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P105-106. Publ Rotterdam: A A Balkema, 1989
A stack of aluminium rods, a two dimensional analogue of a granular material, has been tested in a general stress apparatus, in which the two compressive stresses and the shear stress can be applied directly and independently. The dependency of strain on principal stress rotation and general stress path is examined. Results are analysed using a proposed constitutive model in which general strain increments are directly related to general stress increments.
Soil engineers traditionally use deterministic analysis, and little attention is paid to uncertainties in data. Three areas in which correct treatment can improve reliability of information and design are examined. Scatter of results must be considered in design calculations. Test equipment must be regularly checked to minimise possibility of erroneous results. Conservation amongst engineers, resulting in resistance to use of new data or test techniques, must be overcome.
© 1990 Pergamon Press plc. Reproduction not permitted
906078 Unconfined compression strength of soft aged clays Ohta, H; Nishihara, A; Iizuka, A; Morita, Y; Fukagawa, R; Arai, K Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P71-74. Publ Rotterdam." A A Balkema, 1989
Shear band formation for sands under biaxial stress was studied in the laboratory, with particular interest in the role of mean stress. A significant influence of confining stress on appearance of strain localization was seen. Increasing delay in strain localization with tendency to contractive behaviour was observed. The question of applicable deformation mechanisms for strain localization in contractive materials remains unanswered.
The use of UCS in stability analysis of soft aged clays is discussed considering residual effective stress in the so-called undisturbed samples. The method of Ohta (1983) was used to measure residual effective stress on clay samples from 22 sites across Japan. Interpretation of test results using an elastoplastic constitutive model leads to derivation of a correction factor to account for effects of sampling disturbance on UCS for use in conventional slip surface analysis. If this is applied, the UCS is in good agreement with values back calculated from failure analysis.
906O75 Gmax measured in oedometer and DSS tests using bender elements Dyvik, R; Olsen, T S Proc 12th International Conference on Soil Mechtmics and Foundation Engineering, Rio de Janoiro, 13-18 August 1989 V1, P39-42. Publ Rotterdam: A A Balkema, 1989
906079 Validation of failure models for granular soils Puccini, P; Saada, A; Bianchini, G Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P89-92. Publ Rotterdam: A A Balkema, 1989
Gmax was measured for Drammen clay, using piezoceramic bender elements mounted in oedometer, direct simple shear and triaxial devices. Results from the different tests at different levels of consolidation are compared. Gmax was easily and accurately determined using the DSS and oedometer devices, and values at comparable stages of consolidation are consistent. These results indicate the computational method and assumptions concerning shear wave travel in the bender elements are correct.
Over 250 hollow cylinder and true triaxial tests were carried out on three sands by Case Western Reserve and Grenoble universities. Test data were used to evaluate the Mohr Coulomb, William and Warnke, Lade, and Matsuoka and Akai failure criteria, and in development of a new tensor polynomial model. The Lade criterion is the most attractive for isotropic materials, the new model if anisotropy is taken into account.
906076 Strength and deformation of partly saturated soils Escario, V; Juca, J F T; Coppe, M S Proc 12th International Conference on Soil Mechanics and Foundation Engincering, Rio de Janeiro, 13-18 August 1989 VI, P43-46. Publ Rotterdam: A A Balkema, 1989
9O608O Versatile triaxial equipmentin the University of Oulu Ravaska, O; Kujala, K; Kallio, V Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P97-100. Publ Rotterdam: A A Balkema, 1989
Penetration and direct shear tests with controlled suction (up to 15MPa) were carried out on samples of two clays and a clayey sand. Factors affecting time to equilibrium are considered. Penetration tests indicate increase in deformation modulus and resistance with Suction, up to a maximum. Direct shear tests show similar behaviour, but with gentle decline once the maximum is reached. An elliptical relation is seen between shear strength and suction.
A conventional (Geonor K - I I ) triaxial cell has been automated and modified at the University of Oulu, Finland. It is capable of constant load and constant strain rate tests, and sensitive temperature control enables testing of frozen, freezing, and thawing soils. The cell design, control, and data acquisition are described. Some test results from shear and creep tests on frozen silt, and frost heave from a freezing test on glacial till are presented.
906077 General stress tests on granular materials Matsuoka, H; Suzuki, Y; Murata, T Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janciro, 13-18 August 1989 VI, P65-68. Publ Rotterdam: A A Balkema, 1989
906081 Quality assurance in laboratory testing Sallfors, D Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 V1, P105-106. Publ Rotterdam: A A Balkema, 1989
A stack of aluminium rods, a two dimensional analogue of a granular material, has been tested in a general stress apparatus, in which the two compressive stresses and the shear stress can be applied directly and independently. The dependency of strain on principal stress rotation and general stress path is examined. Results are analysed using a proposed constitutive model in which general strain increments are directly related to general stress increments.
Soil engineers traditionally use deterministic analysis, and little attention is paid to uncertainties in data. Three areas in which correct treatment can improve reliability of information and design are examined. Scatter of results must be considered in design calculations. Test equipment must be regularly checked to minimise possibility of erroneous results. Conservation amongst engineers, resulting in resistance to use of new data or test techniques, must be overcome.
© 1990 Pergamon Press plc. Reproduction not permitted