Thesis (Ph. D.)--Washington State University, December 2006. / Includes bibliographical references (p. 135-149).

Thesis (M.S.)--Joint Program in Oceanography/ Applied Ocean Science and Engineering, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 2006. / "September 2006." Bibliography: p. 94-96.

Zugl.: Berlin, Techn. Universiẗat, Diss., 2000.

Tübingen, Universiẗat, Diss., 2002. / Dateiformat: tgz, Dateien in unterschiedlichen Formaten.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 176-183). Also available in electronic version.

Thesis (Ph. D.)--University of Chicago, 1917. / "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "Reprinted from the Botanical gazette, Vol. LXVIII, No. 1 July, 1919." "Literature cited": p. 51-53.

Thèse--Lettres--Paris, 1919. / Bibliogr. p. 633-657. Bibliogr. p. 356-366. Index.

The Full-Displacement Pressuremeter (FDPM) Test is one in which a pressuremeter is installed in the soil by pushing it behind a conical tip. Earlier work had indicated that the unload-reload modulus measured with the FDPM was very similar to that obtained from self-boring pressuremeter (SBPM) testing. It had also been suggested that if the pressuremeter was capable of sufficient expansion, the interpreted soil properties would be those of the soil beyond the zone of disturbance. This study examined the factors affecting the measurement, analysis and interpretation of soil properties from FDPM pressure-expansion curves in sands with emphasis on the unload-reload modulus. The effects of equipment design and dimensions, installation method and of test procedure on the analysis and interpretation of lateral stress, shear strength and stiffness were studied during laboratory and field evaluation of two prototype FDPMs. The overwhelming importance of instrument dimensions and tolerances on the test results was clearly shown. Movements of a fraction of a millimetre can have a large effect on the measured lateral stress and stiffness. Test procedures were also shown to have a large effect on the data obtained. It was demonstrated that rate effects became important in pressuremeter tests involving expansion to large strains and a stress-strain strain rate concept was proposed to aid in the understanding of these effects. Theories developed for the interpretation of shear strength of sands from SBPM tests were shown to be inapplicable to the interpretation of FDPM test results. The unload-reload modulus was shown to be an indicator of soil stiffness but the effects of stress level and degree of unloading have to be considered when attempting to derive a stiffness for design. A rational approach to the interpretation of modulus was presented and it was shown that unload-reload moduli from both SBPM and FDPM could be interpreted using the same approach. The need for standardising the equipment design, testing procedures and methods of analysis and interpretation was shown. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Drained behaviour of sands under simultaneous increase in stress ratio and principal stress rotation is investigated. The hollow cylinder torsional (HCT) device which permits independent control of four stress parameters: mean normal stress σ'[subscript]m, stress ratio R, intermediate principal stress parameter b and the inclination α[subscript]σ of σ'₁ to the vertical, is adopted as the testing device. In order to conduct complex stress path testing in the HCT device, a new automatic stress path control system is developed. The stress non-uniformities due to the curvature of the HCT specimen is assessed using an incremental elastic representation of sand behaviour, in order to delineate the domain of stress space that could reliably be explored using the HCT device. It is shown that previous assessments of stress non-uniformities assuming linear elastic soil grossly overestimate the stress non-uniformities in a HCT sand specimen. A much larger domain of stress space with acceptable levels of non-uniformities is apparent from the results of incremental elastic analysis. New domain of stress space for reliable exploration using the HCT device is delineated and the testing program is developed so that all stress paths lie within these acceptable limits. Tests are carried out on pluviated sand under saturated drained conditions. The deformations under increasing R and α[subscript]σ is shown to be path independent, if the final stress state is within the approximate bounds of R ≤ 2 and α[subscript]σ ≤ 45°, regardless of the b or relative density D[subscript]r, levels. With increasing stress ratio R and/or principal stress rotation α[subscript]σ, the deformations gradually become path dependent. Once loaded to a stress state within the domain R ≤ 2 and α[subscript]σ ≤ 45°, the strain response under subsequent principal stress rotation is shown to be independent of the previous loading history. It is demonstrated that the strain response under any general increasing R - α path in the domain of R ≤ 2 and α[subscript]σ ≤ 45° can be predicted using the results of a limited number of tests characterizing that domain. It is shown that these concepts can be extended to loading paths which involve simultaneous increase of three stress parameters. Strain increment direction α[subscript]Δε is shown to be approximately coincident with and totally governed by the stress increment direction α[subscript]Δσ when the stress increment direction α[subscript]Δσ is more inclined towards the vertical deposition direction. When the stress increment direction is inclined closer to the bedding plane, the strain increment direction depends in addition, on other parameters such as R, α[subscript]σ and R[subscript]r etc. Under any stress path involving principal stress rotation, the deformations decrease with increasing density and therefore the principal stress rotation is more crucial in loose sands. Deformations increase with the level of stress ratio R. Level of b parameter does not affect deformations under principal stress rotation, if the rotations are small. However, with increasing α[subscript]σ deformations due to principal stress rotation tend to increase with decreasing b value. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Stress path and prestrain effects on the monotonic and cyclic undrained behaviour of a saturated sand are investigated in the triaxial test. It is shown that under Identical consolidation stresses, the sand is contractive over a much larger range of relative densities in triaxial extension than in triaxial compression. The effective stress ratio at the initiation of contractive deformation (CSR) in extension is less than that in compression. During cyclic loading this feature makes the extension phase of the loading more damaging than the compression phase. The unique relationship between void ratio and undrained strength at PT state (which is similar to steady state line) noted in compression does not hold in extension. A separate relationship seems to emerge in extension for each initial void ratio and all such relationships lie to the left of the compression relationship, implying smaller PT state strengths in extension than in compression at equal void ratios. A small prestrain history (stress state staying within CSR lines during prestraining) is shown not to alter the initially liquefiable character of sand. With no strain reversal on reloading, increasing prestrain strain level between CSR and PT lines makes the sand. Strain reversal on reloading, on the other hand, causes the sand to become more contractive with increasing prestrain history and may transform an initially dilative to contractive sand. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate