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Performance of an anisotropic clay under variable stresses

In the true triaxial test procedure used for testing laboratory-prepared kaolinite clay samples, undrained (with constant mean stress) strength tests were conducted to study the yield and failure of the clays. The principle concern focussed around the influence of orientation of particle bedding plane on the development of yield and failure characteristics of the clay. As the true triaxial cell permits variations of the three principal stresses, it was possible to study the soil response in any chosen quadrant of the principal space. / As a consequence to what is mentioned above, two types of consolidated undrained true triaxial tests were conducted in this study. In the first type, specimens were trimmed from the block sample with 90, 60, 30 and 0 degree orientation angles of particle's bedding planes; these angles were measured with respect to the direction of the major principal stress axis. For each degree of inclination, specimens were tested with three confining pressures 207, 276 and 345 kPa, and for each value of confining pressure, the loading path was varied from compression to tension. / The degree of dissociation between the stress and strain increment vectors was seen to depend on both initial and stress induced anisotropy. / Most important of all, a constitutive relationship for anisotropic kaolinite clay was derived on the basis of the observed experimental behaviour of soil samples under loading. / Additionally, anisotropy is characterized by a double transformation technique. The first transformation accounts for the directional dependency whilst the second transformation concerns itself with anisotropy of the base vectors. The relative joint invariant principle is used to calculate the degree of dissociation during the loading process. The variation of the dissociation angle during the loading process can be considered as a measure of the evolution of the resultant anisotropy. The model has shown to provide viable predictions of the stress-strain relationships obtained from true triaxial tests on an anisotropic kaolinite clay for: (a) different inclinations of particle's bedding planes, (b) different stress paths in one sector, (c) different stress paths in other sectors, and (d) the failure surfaces for different inclinations of particle's bedding planes in the octahedral plane. (Abstract shortened with permission of author.)

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75342
Date January 1986
CreatorsMohamed, Abdel-Mohsen Onsy.
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageDoctor of Philosophy (Department of Civil Engineering and Applied Mechanics.)
RightsAll items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated.
Relationalephsysno: 000417691, proquestno: AAINL38170, Theses scanned by UMI/ProQuest.

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