| Summary: | 碩士 === 中原大學 === 土木工程研究所 === 94 === Plate shearing exerts a horizontal shear force to cause lateral displacement and rearrangement of soil grains. In this way, sand grains are closely packed.
The purpose of this study is to probe into the effect of type of plate shearing on the relative density and cone penetration resistance of sands. With changing the normal stress, the thickness of specimen, and the type of plate shearing, a series of tests are conducted and the compression and the cone penetration resistance of the specimen are measured. Diameter of the specimen is 20 cm. The specimens of the Mailiao sand, Ottawa sand and Vietnam sand were carried out with initial relative density of 30%. Normal stresses of 20 kPa, 60 kPa and 100 kPa, one-way shear angle 10°, 20°, 30°, 60°, 90°, and different accumulated angle were used.
The results of this study show that the relative density of the specimen will increase with the accumulated angle of shearing to a maximum value. This maximum value is directly proportional to the normal stress. The initial thickness of soil specimen affects the improvement of relative density. The smaller thickness of the specimen, the better is the improvement result; flaky and small Mailiao sand is improved better than the chunky and larger Ottawa sand and Vietnam sand. The relationship between the improvement of relative density and the reversal number of times is clear, and it is suggested that one-way shear angle of reversal plate shearing is better at 10°~30°.
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