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Effect of clay content on liquid limit from a fall cone and the British cup device. Technical note
5A rate of wetting or to the water potential used. Multiple wetting cycles suggested that an equilibrium state could be reached for soil properties such as strength and structure, The cause of the softening is taken to be the formation of microcracks on wetting and drying.
861035 Effect of clay content on liquid limit from a fall cone and the British cup-device. Technical note Budhu, M Geotech Test J I/8, N2, June 1985, P91-95
861031 Study of the mechanical behaviour of sand impregnated with bitumen (In French) Royis, P; Di Benedetto, H Bull Liaison Lab Ponts Chaussees N136, March-April 1985, P65-72
Liquid limit values measured with fall cones of the same angle but different weights agree closely with those measured by the British cup device, provided the appropriate depth of penetration is specified. Differences in the observed values are attributed to differences in clay content of the soils and its (clay) behaviour under the different deformation modes. A one point fall cone method is shown to be sufficiently accurate to deduce the liquid limit of soils. It is suggested that for engineering purposes, liquid limit could be defined as the water content at which a soil has a specified undrained shear strength.
The principal results of a programme of cyclic triaxial tests carried out on samples o f sand impregnated with bitumen are analysed. The material used, the experimental equipment and instrumentation and the tests are described. The similarities and differences between the behaviour of the material studied and that of other granular materials (sand, clay) are presented. Viscoelastic behaviour is evident and a nonlinear constitutive relationship describing the behaviour is proposed.
861032 Effect of consolidation history and stress path on hyperbolic stress-strain relations Vaid, Y P Can Geotech J I~2, N2, May 1985, P172-176 The hyperbolic approximation of the stress-strain behaviour of soil based on the results of triaxial tests, which is used in incremental elastic analysis of soil deformation problems, is shown to be inapplicable for representing soil behaviour under anisotropic consolidation and different stress paths. Test results on a normally consolidated clay are presented to show that a separate hyperbolic representation of stress-strain is possible for each consolidation history and stress path if increment in deviator stress after consolidation, rather than deviator stress, is used as the stress variable. Hyperbolic parameters are thus shown to depend on test type. Auth.
861033 Performance of an elastoplastic model Evgin, E; Eisenstein, Z Can Geotech J V22, N2, May 1985, P177-185 Lade's original elastoplastic work hardening model for cohesionless soils (1975) is reviewed and the nongenerality of the work hardening rule pointed out. A new assumption is introduced allowing the model to be used for general boundary value problems. The predictions of load-deformation responses and stress distribution for a wall compare well with in situ measurements. Results indicate the model may reliably predict the behaviour of soil structures under a wide range of loading conditions.
861034 Direct tensile loading apparatus combined with a cubical test cell for testing rocks and concrete Meier, R W: Ho, H K; Sture, S Geotech Test J V8, N2, June 1985, P71-78 Apparatus is described which allows the application of simultaneous tensile and compressive stresses to a cubic specimen with a minimum of boundary constraint, and the accurate measurement of resultant deformations. It can be usefully employed to examine the fracture modes of brittle materials. Test results on rocks and concrete demonstrate the capabilities of the multiaxial tensile-compressive technique. R . M M S. 23 I
H
861036 Underwater instrument for determining bearing capacity of shallow marine sedSments. Technical note Circe, R C Geotech Test J VS, N2, June 1985, P96-98 A small, portable device has been developed to measure bearing capacity in shallow water carbonate reef environments. The concepts for design and operation were derived from the ASTM test method for bearing capacity of soil for static load on spread footings (ASTMD 1194). It can deliver controlled levels of stress to bearing plates of various sizes, is transportable, simple to use underwater and reasonably priced.
86 ! 037 Plasticity of compressible/dilatant rocklike materials Cristescu, N Int J Engng Sci V23, NIO, 1985, P1091-1100 An elastic/plastic constitutive equation is presented which can be adapted to any rocklike material and can describe both dilatancy and compressibility. Mathematical definitions are given for dilatancy, the dilatancy threshold boundary and compressibility. The parameters in the constitutive equation can be determined from experimental data. The model is established for any stress state, and may be used for finding the stress, strain and displacement fields around underground openings. The constitutive equation must, in this case, be formulated with the in situ primary stresses taken into account. The constitutive equation for granite is evaluated from laboratory test data.
861038 Continuous plasticity version of the critical state model Naylor, D J lnt J Num Meth Engng V21, NT, July 1985, P1187-1204 The conventional critical state model for soils is modified by introducing some plasticity into the stress region which is normally fully elastic, blurring the otherwise sharp distinction between elastic and yielding states. It provides a more robust constitutive law for finite element modelling and a more realistic soil model for monotonic loading and for cyclic loading with a limited number of cycles. The model has been used to simulate a set of triaxial tests, an isotropic test and a onedimensional test on compacted clayey fill. A close fit was obtained for 3 of 5 stress-strain curves.
861035 Effect of clay content on liquid limit from a fall cone and the British cup-device. Technical note Budhu, M Geotech Test J I/8, N2, June 1985, P91-95
861031 Study of the mechanical behaviour of sand impregnated with bitumen (In French) Royis, P; Di Benedetto, H Bull Liaison Lab Ponts Chaussees N136, March-April 1985, P65-72
Liquid limit values measured with fall cones of the same angle but different weights agree closely with those measured by the British cup device, provided the appropriate depth of penetration is specified. Differences in the observed values are attributed to differences in clay content of the soils and its (clay) behaviour under the different deformation modes. A one point fall cone method is shown to be sufficiently accurate to deduce the liquid limit of soils. It is suggested that for engineering purposes, liquid limit could be defined as the water content at which a soil has a specified undrained shear strength.
The principal results of a programme of cyclic triaxial tests carried out on samples o f sand impregnated with bitumen are analysed. The material used, the experimental equipment and instrumentation and the tests are described. The similarities and differences between the behaviour of the material studied and that of other granular materials (sand, clay) are presented. Viscoelastic behaviour is evident and a nonlinear constitutive relationship describing the behaviour is proposed.
861032 Effect of consolidation history and stress path on hyperbolic stress-strain relations Vaid, Y P Can Geotech J I~2, N2, May 1985, P172-176 The hyperbolic approximation of the stress-strain behaviour of soil based on the results of triaxial tests, which is used in incremental elastic analysis of soil deformation problems, is shown to be inapplicable for representing soil behaviour under anisotropic consolidation and different stress paths. Test results on a normally consolidated clay are presented to show that a separate hyperbolic representation of stress-strain is possible for each consolidation history and stress path if increment in deviator stress after consolidation, rather than deviator stress, is used as the stress variable. Hyperbolic parameters are thus shown to depend on test type. Auth.
861033 Performance of an elastoplastic model Evgin, E; Eisenstein, Z Can Geotech J V22, N2, May 1985, P177-185 Lade's original elastoplastic work hardening model for cohesionless soils (1975) is reviewed and the nongenerality of the work hardening rule pointed out. A new assumption is introduced allowing the model to be used for general boundary value problems. The predictions of load-deformation responses and stress distribution for a wall compare well with in situ measurements. Results indicate the model may reliably predict the behaviour of soil structures under a wide range of loading conditions.
861034 Direct tensile loading apparatus combined with a cubical test cell for testing rocks and concrete Meier, R W: Ho, H K; Sture, S Geotech Test J V8, N2, June 1985, P71-78 Apparatus is described which allows the application of simultaneous tensile and compressive stresses to a cubic specimen with a minimum of boundary constraint, and the accurate measurement of resultant deformations. It can be usefully employed to examine the fracture modes of brittle materials. Test results on rocks and concrete demonstrate the capabilities of the multiaxial tensile-compressive technique. R . M M S. 23 I
H
861036 Underwater instrument for determining bearing capacity of shallow marine sedSments. Technical note Circe, R C Geotech Test J VS, N2, June 1985, P96-98 A small, portable device has been developed to measure bearing capacity in shallow water carbonate reef environments. The concepts for design and operation were derived from the ASTM test method for bearing capacity of soil for static load on spread footings (ASTMD 1194). It can deliver controlled levels of stress to bearing plates of various sizes, is transportable, simple to use underwater and reasonably priced.
86 ! 037 Plasticity of compressible/dilatant rocklike materials Cristescu, N Int J Engng Sci V23, NIO, 1985, P1091-1100 An elastic/plastic constitutive equation is presented which can be adapted to any rocklike material and can describe both dilatancy and compressibility. Mathematical definitions are given for dilatancy, the dilatancy threshold boundary and compressibility. The parameters in the constitutive equation can be determined from experimental data. The model is established for any stress state, and may be used for finding the stress, strain and displacement fields around underground openings. The constitutive equation must, in this case, be formulated with the in situ primary stresses taken into account. The constitutive equation for granite is evaluated from laboratory test data.
861038 Continuous plasticity version of the critical state model Naylor, D J lnt J Num Meth Engng V21, NT, July 1985, P1187-1204 The conventional critical state model for soils is modified by introducing some plasticity into the stress region which is normally fully elastic, blurring the otherwise sharp distinction between elastic and yielding states. It provides a more robust constitutive law for finite element modelling and a more realistic soil model for monotonic loading and for cyclic loading with a limited number of cycles. The model has been used to simulate a set of triaxial tests, an isotropic test and a onedimensional test on compacted clayey fill. A close fit was obtained for 3 of 5 stress-strain curves.