The influence of stress relief on the vane strength of clays

Kirkpatrick, W. M.; Khan, A. J.

doi:10.1680/geot.1984.34.3.428

Cited by 7 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The GOM normally consolidated soil stratigraphy information is presented in Fig. 5,6,7 It would have been useful to have had PCPT soundings at this site to further evaluate the higher insitu vane measurements. This figure shows the liquidity index (LI), vertical effective stress (σ ' v ) and design undrained shear strength (s u ) profiles.…”

Section: Comparison Of Stratigraphiesmentioning

confidence: 99%

Deepwater Soil Properties and Their Impact on the Geotechnical Program

Quirós

Little

2003

All Days

View full text Add to dashboard Cite

The sometimes unpredictable and highly variable nature of soil conditions in deepwater regions must be recognized in planning geotechnical site investigations. Examples of four different soil stratigraphies in deepwater are presented to demonstrate the variability and peculiar nature of some sediments and how important it is to plan for comprehensive programs both in the field and in the laboratory phases of a geotechnical site investigation. The authors will show how reliance on correlations based on index properties and failing to understand their limitations can lead to misinterpretation of soil properties.

show abstract

Section: Comparison Of Stratigraphiesmentioning

confidence: 99%

Deepwater Soil Properties and Their Impact on the Geotechnical Program

Quirós

Little

2003

All Days

View full text Add to dashboard Cite

show abstract

“…In fact some results reported by other authors (Tanaka 1994), show no influence of the vane radius on the measured shear strength. These differences may be due to side effects as sampling disturbance or stress relief for soils used in laboratory vane tests, which would reduce the apparent shear strength (Kirkpatrick and Khan 1984). However, in general, that is taken into account when estimating s u .…”

Section: Time Effectsmentioning

confidence: 99%

“…As there are several factors influencing the result, it is difficult to deal with all of them simultaneously. Even some probabilistic approaches have been presented elsewhere to deal with the uncertainties involving the 'in situ' measurement of the mobilized undrained shear strength (Kirkpatrick and Khan 1984). Recently, a new model to estimate a theoretical torque based on critical state concepts have been presented Williams, 1993, 1994).…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of complex geomechanical problems

Pérez Foguet

View full text Add to dashboard Cite

La tesis se centra en el desarrollo de técnicas numéricas específicas para la resolución de problemas de mecánica de sólidos, tomando como referencia aquellos que involucran geomateriales (suelos, rocas, materiales granulares,...). Concretamente, se tratan los siguientes puntos: 1) formulaciones Arbitrariamente Lagrangianas Eulerianas (ALE) para problemas con grandes desplazamientos del contorno; 2) métodos de resolución para problemas no lineales en el campo de la mecánica de sólidos y 3) modelización del comportamiento mecánico de materiales granulares mediante leyes constitutivas elastoplásticas. Las principales aportaciones de la tesis son: el desarrollo de una formulación ALE para modelos hyperelastoplásticos y el cálculo de operadores tangentes para distintas leyes constitutivas y esquemas de integración temporal no triviales (uso de esquemas de derivación numérica, técnicas de subincrementación y modelos elastoplásticos con endurecimiento y/o reblandecimiento dependientes del trabajo plástico o la densidad). Se presentan diversas aplicaciones que muestran las principales características de los desarrollos presentados (análisis del ensayo del molinete para arcillas blandas, del ensayo triaxial para arenas, de la rotura bajo una cimentación, del proceso de estricción de una barra metálica circular y de un proceso de estampación en frío), dedicando una especial atención a los aspectos computacionales de la resolución de dichos problemas. Por último, se dedica un capítulo específico a la modelización y la simulación numérica de procesos de compactación fría de polvos metálicos y cerámicos. Numerical modelling of problems involving geomaterials (i.e. soils, rocks, concrete and ceramics) has been an area of active research over the past few decades. This fact is probably due to three main causes: the increasing interest of predicting the material behaviour in practical engineering situations, the great change of computer capabilities and resources, and the growing interaction between computational mechanics, applied mathematics and different engineering fields (concrete, soil mechanics...). This thesis fits within this last multidisciplinary approach. Based on constitutive modelling and applied mathematics and using both languages the numerical simulation of some complex geomechanical problems has been studied. The state of the art regarding experiments, constitutive modelling, and numerical simulations involving geomaterials is very extensive. The thesis focuses in three of the most important and actual ongoing research topics within this framework: 1) the treatment of large boundary displacements by means of Arbitrary Lagrangian-Eulerian (ALE) formulations; 2) the numerical solution of highly nonlinear systems of equations in solid mechanics; and 3) the constitutive modelling of the nonlinear mechanical behaviour of granular materials. The three topics have been analysed and different contributions for each one of them have been developed. Moreover, some of the new developments have been applied to the numerical modelling of cold compaction processes of powders. The process consists in transforming a loose powder into a compacted sample through a large volume reduction. This problem has been chosen as a reference application of the thesis because it involves large boundary displacements, finite deformations and highly nonlinear material behaviour. Therefore, it is a challenging geomechanical problem from a numerical modelling point of view. The most relevant contributions of the thesis are the following: 1) with respect to the treatment of large boundary displacements: quasistatic and dynamic analyses of the vane test for soft materials using a fluid-based ALE formulation and different non-newtonian constitutive laws, and the development of a solid-based ALE formulation for finite strain hyperelastic-plastic models, with applications to isochoric and non-isochoric cases; 2) referent to the solution of nonlinear systems of equations in solid mechanics: the use of simple and robust numerical differentiation schemes for the computation of tangent operators, including examples with several non-trivial elastoplastic constitutive laws, and the development of consistent tangent operators for different substepping time-integration rules, with the application to an adaptive time-integration scheme; and 3) in the field of constitutive modelling of granular materials: the efficient numerical modelling of different problems involving elastoplastic models, including work hardening-softening models for small strain problems and density-dependent hyperelastic-plastic models in a large strain context, and robust and accurate simulations of several powder compaction processes, with detailed analysis of spatial density distributions and verification of the mass conservation principle.

show abstract

Analysis of the vane test considering size and time effects

Foguet

Ledesma

Huerta

1999

Int. J. Numer. Anal. Meth. Geomech.

View full text Add to dashboard Cite

An analysis of the vane test using an Arbitrary Lagrangian}Eulerian formulation within a "nite element framework is presented. This is suitable for soft clays for which the test is commonly used to measure in situ undrained shear strength. Constitutive laws are expressed in terms of shear stress}shear strain rates, and that permits the study of time e!ects in a natural manner. An analysis of the shear stress distributions on the failure surface according to the material model is presented. The e!ect of the constitutive law on the shear band amplitude and on the position of the failure surface is shown. In general, the failure surface is found at 1}1)01 times the vane radius, which is consistent with some experimental results. The problem depends on two dimensionless parameters that represent inertial and viscous forces. For usual vane tests, viscous forces are predominant, and the measured shear strength depends mainly on the angular velocity applied. That can explain some of the comparisons reported when using di!erent vane sizes. Finally, the range of the shear strain rate applied to the soil is shown to be fundamental when comparing experimental results from vane, triaxial and viscosimeter tests. Appart from that, an experimental relation between undrained shear strength and vane angular velocity has been reproduced by this simulation.

show abstract

The influence of stress relief on the vane strength of clays

Cited by 7 publications

References 1 publication

Deepwater Soil Properties and Their Impact on the Geotechnical Program

Deepwater Soil Properties and Their Impact on the Geotechnical Program

Numerical modelling of complex geomechanical problems

Analysis of the vane test considering size and time effects

Contact Info

Product

Resources

About