UBC Theses and Dissertations
The effect of gradation and fines content on the undrained loading response of sand Kuerbis, Ralph H.
A systematic study of the effect of grain size, gradation and silt content on the monotonic and cyclic undrained loading response of sand is presented. The objective of the study is to gain an improved understanding of the behaviour of fluvial and hydraulic fill sands. A slurry method of deposition is developed to prepare homogeneous specimens of well-graded and silty sands, and to simulate hydraulic fill or fluvial deposition processes. Various soil gradations consolidated from loosest state of slurry deposition are shown to have similar triaxial compression loading behaviour, but quite different triaxial extension loading behaviour. Well-graded sands are shown to be generally more resistant to soil liquefaction. Loose silty sands are shown to possess similar cyclic strengths regardless of silt content, even though they have widely different void ratios. The concept of sand skeleton void ratio is introduced in order to explain the observed behaviour of silty sands with varying fines content. The effect of soil sample preparation technique on laboratory test results is discussed. Water pluviated sand is shown to have a characteristic fabric and strength anisotropy. An interpretation of the factors which contribute to sand fabric and strength anisotropy is provided. The practical performance of water pluviated sand is discussed.
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