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Pore pressure predictions in finite element analysis
69A aperture. The second, the multi joint geometry parameter, describes spacing, offset, persistence and overlap ratio. The method is used to model en-echelon jointed rock masses.
902033 Stratigraphical and geotechnicai correlated properties of Belgian loess Huergo, P J; Crespo, E Q Proc International Conference on Engineering Problems of Regional Soils, Beijing, 11-15 August 1988 P241-246. Publ Beijing: International Academic Publishers, 1989 Origin, geological and stratigraphic descriptions of loess soils in Belgium are presented. Grain size distribution, plasticity, activity, compressibility, consolidation, and collapse properties and their variation with depth have been determined. Comparison of the two data sets indicates that stratigraphic data can be used to assess geotechnical properties. All sediments are preconsolidated, with degree varying with age. Several geotechnical mapping units are defined, but verification of local stratigraphy is necessary before they can be used in engineering work.
902034 Naturally occurring gravels for road construction Hight, D W; Toll, D G; Grace, H Proc 2nd International Conference on Geomeehanics in Tropical Soils, Singapore, 12-14 December 1988 VI, P405412. Publ Rotterdam: A A Balkema, 1988 A laboratory study into the natural laterite and quartz gravels used as road bases in Kenya was undertaken to identify key factors responsible for good performance. Grain size distribution, Atterberg limits and clay activity, fabric, suction, permeability and strength were analysed. It seems the gravels offer good performance as they are widely graded and show dilatant behaviour under shear for most densities and good compactability.
Deformation and strength characteristics See also: 902204. 902205, 902220, 902242, 902243, 902245, 902246, 902035 Strength of frozen sand containing tetrahydrofuran hydrate. Note Parameswaran, V R; Paradis, M; Handa, Y P Can Geotech J V26, N3, Aug 1989, P479-483 Frozen hydrates are encountered in gas and oil fields in arctic regions. Their physical and mechanical properties are little known. Tetrahydrofuran hydrate is easily formed in the laboratory. Cylindrical samples of sand containing frozen T H F hydrate and ice were tested under uniaxial compression at various strain rates. The sand containing THF was the stronger at low strain rates but its strain rate sensitivity is such that as strain rate is increased, the two frozen soils show comparable strengths.
902036 Thin-sample technique of residual strength measurement. Technical note Chandler, R J; Hardie, T N Geotechnique 1/39, N3, Sept 1989, P527-531 Thin sample techniques, which use widely available apparatus, have been largely abandoned since the advent of the ring shear apparatus. Results are presented for tests on 60mm square
samples in a direct shear apparatus. Samples were consolidated in stages between porous stones. Over and normally consolidated specimens of thickness 1.5-10mm were tested. The influence of inaccurate centring of the specimen was studied. Results indicate these tests provide quick and accurate determinations of residual strength, more satisfactory than those from 10-20mm thick specimens.
902037 Crystalline calcite in till: engineering implications. Technical note
Little, J A Geotechnique 1/39. N3, Sept 1989, P533-541 Two glacial tills from the UK, one a chalky till containing crystalline calcite and the other from a naturally decalcified horizon, are compared. Mineralogy and elemental composition were determined by x-ray analysis. Oedometer compression characteristics for reconstituted and undisturbed samples, variation of undrained strength with liquidity index, and scanning electron microscopy of the tills are illustrated. Results are discussed with reference to soil pedogenesis and engineering properties.
902038 Elastic-plastic response of a circular hole to repeated loading Senseny, P E; Lindberg, H E; Schwer, L E lnt J Num Anal Meth Geomech VI3, N5, Sept-Oct 1989, P459-476 An analytical solution is obtained to the problem of repeated axisymmetric loading of an infinite Mohr-Coulomb material containing a circular hole. After application of an initial farfield load, pressure is reduced to zero then increased up to and above the pressure at which the cycle began. The solution is used to predict results of tests on a rock-like material containing a reinforced hole. Closure is influenced by internal pressure, working load, and friction angle and compressive strength of the material. Closure increments per load cycle at small closures are small compared to initial closure, comparable and cumulative.
902039 Pore pressure predictions in finite element analysis Pacheco, M P; Altschaeffl, A G; Chameau, J L lnt J Num Anal Meth Geomech V13, N5, Sept-Oct 1989, P477-491 A pore pressure model including simultaneous effects of shear and mean confining stress is presented. As it is difficult to determine strains using the FEM at sufficient accuracy to ensure satisfactory pore pressure predictions, the proposed model uses a pore pressure function coupled to a potential and a loading function in an elasto-plastic constitutive model. Assumptions made and limitations of the procedure are discussed. The advantages of the model for pore pressure prediction during undrained loading are demonstrated.
902040 Strain-path analyses for arbitrary three-dimensional penetrometers Huang, A B lnt J Num Anal Meth Geomech VI3, NS, Sept-Oct 1989, P551-564 A numerical technique based on the theory of potential flow and the panel method is presented. It is used to model the 'flow' of soil due to the penetration of a cone and a flat Marchetti dilatometer. Results show the responses of soils to these two types of penetrometer are fundamentally different.
© 1990 Pergamon Press plc. Reproduction not permitted RMMS 27 2--F
902033 Stratigraphical and geotechnicai correlated properties of Belgian loess Huergo, P J; Crespo, E Q Proc International Conference on Engineering Problems of Regional Soils, Beijing, 11-15 August 1988 P241-246. Publ Beijing: International Academic Publishers, 1989 Origin, geological and stratigraphic descriptions of loess soils in Belgium are presented. Grain size distribution, plasticity, activity, compressibility, consolidation, and collapse properties and their variation with depth have been determined. Comparison of the two data sets indicates that stratigraphic data can be used to assess geotechnical properties. All sediments are preconsolidated, with degree varying with age. Several geotechnical mapping units are defined, but verification of local stratigraphy is necessary before they can be used in engineering work.
902034 Naturally occurring gravels for road construction Hight, D W; Toll, D G; Grace, H Proc 2nd International Conference on Geomeehanics in Tropical Soils, Singapore, 12-14 December 1988 VI, P405412. Publ Rotterdam: A A Balkema, 1988 A laboratory study into the natural laterite and quartz gravels used as road bases in Kenya was undertaken to identify key factors responsible for good performance. Grain size distribution, Atterberg limits and clay activity, fabric, suction, permeability and strength were analysed. It seems the gravels offer good performance as they are widely graded and show dilatant behaviour under shear for most densities and good compactability.
Deformation and strength characteristics See also: 902204. 902205, 902220, 902242, 902243, 902245, 902246, 902035 Strength of frozen sand containing tetrahydrofuran hydrate. Note Parameswaran, V R; Paradis, M; Handa, Y P Can Geotech J V26, N3, Aug 1989, P479-483 Frozen hydrates are encountered in gas and oil fields in arctic regions. Their physical and mechanical properties are little known. Tetrahydrofuran hydrate is easily formed in the laboratory. Cylindrical samples of sand containing frozen T H F hydrate and ice were tested under uniaxial compression at various strain rates. The sand containing THF was the stronger at low strain rates but its strain rate sensitivity is such that as strain rate is increased, the two frozen soils show comparable strengths.
902036 Thin-sample technique of residual strength measurement. Technical note Chandler, R J; Hardie, T N Geotechnique 1/39, N3, Sept 1989, P527-531 Thin sample techniques, which use widely available apparatus, have been largely abandoned since the advent of the ring shear apparatus. Results are presented for tests on 60mm square
samples in a direct shear apparatus. Samples were consolidated in stages between porous stones. Over and normally consolidated specimens of thickness 1.5-10mm were tested. The influence of inaccurate centring of the specimen was studied. Results indicate these tests provide quick and accurate determinations of residual strength, more satisfactory than those from 10-20mm thick specimens.
902037 Crystalline calcite in till: engineering implications. Technical note
Little, J A Geotechnique 1/39. N3, Sept 1989, P533-541 Two glacial tills from the UK, one a chalky till containing crystalline calcite and the other from a naturally decalcified horizon, are compared. Mineralogy and elemental composition were determined by x-ray analysis. Oedometer compression characteristics for reconstituted and undisturbed samples, variation of undrained strength with liquidity index, and scanning electron microscopy of the tills are illustrated. Results are discussed with reference to soil pedogenesis and engineering properties.
902038 Elastic-plastic response of a circular hole to repeated loading Senseny, P E; Lindberg, H E; Schwer, L E lnt J Num Anal Meth Geomech VI3, N5, Sept-Oct 1989, P459-476 An analytical solution is obtained to the problem of repeated axisymmetric loading of an infinite Mohr-Coulomb material containing a circular hole. After application of an initial farfield load, pressure is reduced to zero then increased up to and above the pressure at which the cycle began. The solution is used to predict results of tests on a rock-like material containing a reinforced hole. Closure is influenced by internal pressure, working load, and friction angle and compressive strength of the material. Closure increments per load cycle at small closures are small compared to initial closure, comparable and cumulative.
902039 Pore pressure predictions in finite element analysis Pacheco, M P; Altschaeffl, A G; Chameau, J L lnt J Num Anal Meth Geomech V13, N5, Sept-Oct 1989, P477-491 A pore pressure model including simultaneous effects of shear and mean confining stress is presented. As it is difficult to determine strains using the FEM at sufficient accuracy to ensure satisfactory pore pressure predictions, the proposed model uses a pore pressure function coupled to a potential and a loading function in an elasto-plastic constitutive model. Assumptions made and limitations of the procedure are discussed. The advantages of the model for pore pressure prediction during undrained loading are demonstrated.
902040 Strain-path analyses for arbitrary three-dimensional penetrometers Huang, A B lnt J Num Anal Meth Geomech VI3, NS, Sept-Oct 1989, P551-564 A numerical technique based on the theory of potential flow and the panel method is presented. It is used to model the 'flow' of soil due to the penetration of a cone and a flat Marchetti dilatometer. Results show the responses of soils to these two types of penetrometer are fundamentally different.
© 1990 Pergamon Press plc. Reproduction not permitted RMMS 27 2--F