| Summary: | 碩士 === 國立海洋大學 === 河海工程學系 === 84 === Hydraulic sand fill is one of the most important reclamation
method fornearshore area. It is an economical technology. During
hydraulic sand fill reclamation process, the loss of fine sand
is due to the operation of machines and transportation of soil.
Thus, the properities of filled materials is influenced by the
fine sand content. Therefore, to evaluate the effect of fine
content on dynamics properties of soil in the reclaimation area,
is important for engineering purposes. In this study, the filled
material inYun-Ling nearshore area was adopted as testing
samples. A successful hydraulic sand fill simulation method were
developed in the laboratory, to discuss the packing properties
of the soil aggregates. Different fine sand content (F.C.=0%,
10%, 20%, 30%), different relative density (Dr=40%, 60%, 80%)and
consolidation stress ratio (K=1.0, 1.5, 2.0, 2.5, 3.0) were
taken into consideration. A series of Resonant Column Triaxial
Test were performed by used of Resonant Column Triaxial Test
Apparatus Model DTC-158, to discuss the Shear Modulus (G) and
Damping Ratio (D) of the filled material under initial shear
stress. Normalizing the experiment results, we have the
relation curve of G/Gmax vsShear Strain (γ) and the curve lies
within the upper bound of the curve suggested by Seed and
Idriss, the D-γ curve lies on the lower bound of the suggested
curve. The influence of shear strain and relative density (void
ratio) on dynamics properties of filled soil, has similar effect
on general soil as well. Shear modulus of filled soil will
decrease as the shear strain increases, the damping ratio will
increase as the shear strain increases. The void ratio
decreases as the shear modulus increases. The shear modulus of
filled soil increases as the relative density increases. That
is, the void ratio decreases, the value of Gmax increases. But,
the effect of Void Ratio on Damping Ratio were not distinct.
In this study, to simulate the reclaimed soil under different
initial shearstress, different consolidation stress ratio were
added. As shown in the test results, the shear modulus of the
reclaimed soil would increase as the consolidation stress ratio
increases. Similarly, Gmax increases as the consolidation stress
ratio increases, but would not influence by the different
initial relative density. From the test results, the increment
on Gmax cause by consolidation stress ratio is larger than the
increment cause by different void ratio. The influence of
consolidation stress ratio on damping ratio is not distinct.
Under the same shear strain amplitude, the shear modulus of the
reclaimedsoil would decrease as the fines content increases. For
0% of fine content, there is a maximum value of shear modulus.
The decrease on Gmax cause by fines content is larger than the
increament cause by different void ratio. The damping ratio
increases as the fine content increases, but the influence is
not distinct. Under different shear strain amplitude, the
normalized shear modulus ratioand shear strain stress amplitude
relation curve is discussed. Under different fine content, G/
Gmax would decrease as the fines content increases. Compare the
normalized curve with the bound suggested by Seed and Idriss, as
the fines content increases, the normalized curve approaches the
average curve suggested by Seed and Idriss. By using different
specimen preparation method, as shown in the results,
thespecimen prepared by Hydraulic sand fill method would have
larger maximum shear modulus and shear modulus. This is due to
the soil aggregates in the test sample would help the shear wave
transmition. The influence on damping ratio is not distinct. By
using the test results, the relation between maximum shear
modulus andelastic modulus is proposed. By using the figures in
this paper, the maximum shear modulus of reclaimed soil can be
estimated by traditional triaxial test. Summarizing all the
analyzed results, this study is mainly based on the datafrom the
Resonant Column Triaxial Test, to discuss the influences of
relative density, fine content and consolidation stress ratio on
the dynamics properties of reclaimed soil. And establish
evaluation method, figures and tables of dynamics properties for
reclaimed soil, for reference purposes during foundation and
structure design on reclaimed area.
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