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Granular aggregates of quartz subjected to triaxial compression under constant effective pressures (Pe) undergo macroscopic failure at critical stress states that depend on the effective mean stress. Although the mode of failure and mechanical response vary systematically with mean stress at failure, prefailure loading at subcritical stress states may induce yielding, and subcritical load paths may influence behavior at failure. Here, I investigate how the failure of quartz aggregates at conditions favoring compaction depends on consolidation history and load path in the transitional and ductile deformation regimes in terms of strain localization and microfracture fabric. Three distinct non-standard triaxial compression load paths were employed; the paths involve different preconsolidation of the aggregates at subcritical isotropic stress followed by differential loading with increasing or decreasing confining pressure. Deformed aggregates were injected with epoxy and studied using optical microscopy techniques to determine microscopic damage evolution for the different load paths. Microfracture data show that preconsolidation at subcritical isotropic loads facilitates formation of campaction bands during subsequent triaxial compression in the transitional regime. The preferred orientation of intragranular cracks evolves from near random fabrics for isotropic loading to strongly preferred orientations parallel to the maximum principal compression direction for differential loading, with the strongest preferred orientation within the compaction bands. Aside from the preconsolidation, different load paths have only a minor effect on the mechanical response during macroscopic failure.

Thesis (M.A.)--York University, 2007. Graduate Programme in Music. / Typescript. Includes bibliographical references (leaves 91-92). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004 & res_dat=xri:pqdiss & rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation & rft_dat=xri:pqdiss:MR32036.

Thesis (M.M.)--University of Michigan, 1964.

Thesis (M.M.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (ED.D.)--Teachers College, Columbia University, 1965. / Typescript; issued also on microfilm. Sponsor: Ernest E. Harris. Dissertation Committee: Charles W. Walton. Includes bibliographical references (leaves 244-254).

Thesis (Ed.D.)--Teachers College, Columbia University, 1968. / Typescript; issued also on microfilm. Sponsor: Gladys Tipton. Dissertation Committee: Richard Kraus. Includes bibliographical references.

Thesis (Ed.D.)--Teachers College, Columbia University, 1974. / Typescript; issued also on microfilm. Sponsor: Charles Walton. Dissertation Committee: J. Marion Magill. Includes bibliographical references (leaves 236-241).

Thesis (Ph. D.)--University of Michigan, Ann Arbor, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 97-104). Also issued in print.

Thesis (M.A.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 61-63).