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Thesis (M.S.)--Oregon State University, 1993. / Typescript (photography). Includes bibliographical references (leaves 64-66). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 190-205). Also available in print.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 180-203). Also available in electronic version.

Thesis--Wisconsin. / Vita. Includes bibliographical references (leaves 45-54).

The finite element technique is a powerful method to study the dynamic response of a structure taking into account the effects of ground conditions. However, limitations of computer storage capacity and cost presently prevent its general application to three-dimensional problems. In this thesis it is shown that three-dimensional problems can be analyzed by applying appropriate modification factors to two-dimensional (plane strain) analyses. Modification factors are first determined analytically by comparing the dynamic response of both strip and rectangular footings (uniform shear stress) for a range of input frequencies. It is found that for input frequencies which are less than the fundamental period of the soild layer the modification factor is essentially independent of the input frequency. This suggests that the modification factors could be obtained from static analyses. Modification factors based on static stiffness analyses for both uniform shear stress and uniform shear displacement (rigid foundation) conditions were obtained and were found to be in close agreement with those obtained from the dynamic analyses. Variation of the modification factor with both the depth of the layer and the ratio of the sides of the rectangular base are given in graphical form. These factors may be applied to finite element place strain analysis to predict the dynamic response of three-dimensional structures. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The purpose of this thesis has been to design and develop a practical apparatus for determining the residual strength of clay soils. To provide background for the study, current knowledge regarding residual strength is reviewed, including the following points. 1. Residual strength, defined as the lowest drained strength a soil can exhibit, is attained at large shear displacements. 2. Residual conditions result when particles located in shear bands within the failure zone become aligned in the direction of shear. 3. Residual strength, derived from interparticle bonding, is influenced by crystal structure and, in active clay minerals, by pore water chemistry. The ring shear test, performed by applying a torsional shear load to an annular shaped specimen, is particularly suited for residual strength determinations because of unlimited uni-directional strain capabilities. The UBC Ring Shear Device was designed to combine versatility with uncomplicated operation. Features of the design are as follows. 1. Variable sample height up to 0.75 inches. 2. Smoothly variable normal stress up to 200 psi delivered through an air piston. 3. Smoothly variable rate of shear from 3-2 inches per year to 9 inches per hour. 4. A non-tilting loading platen which reduces required machine tolerances and improves control of sample losses during testing. 5. Automatic data acquisition. 6. A simple method of sample placement. Residual strength determinations obtained with the UBC Ring Shear Device demonstrate its efficient and effective operation. Minimal supervision is required and test results are easily interpreted. Multi-reversal direct shear tests for residual strength were undertaken for comparison with the ring shear results, but no satisfactory results were obtained due to excess pore pressures within the test specimens. Recommendations for improvements to both ring shear and direct shear devices are given. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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