碩士 / 國立海洋大學 / 河海工程學系 / 84 / AbstractHydraulic sand fill is one of the most important
reclamation method in land reclamation process. The reclaimed
soil was transported by pumps and machines to the reclamation
area. During the reclamation process, the excavation of soil
would induce changes in the seafloor. Therefore, the assessment
on the stability of excavated seafloor area is an important
research topic.In this study, a numerical model based on
Discontinuous Deformation Analysis (DDA) is generated for the
assessment on the stability of excavated seafloor. DDA is
similar to Finite Element Method (FEM) where the equations are
listed in the similar manners. But, DDA has a discontinuous
boundaries among the elements. Therefore, based on the
dicontinuous concepts in DDA, the behaviors among the soil
particles can be simulated. However, DDA does not incorporate
drained conditions between In this study, modifications are
tried to improve this deficiency. In this study, the
deformation features in the seafloor are identified. Finally,
a practical model is proposed based on the concept of DDA by
Shi, and based on Linear Wave Theory, and considering wave
loading to the upper surface of the seafloor, for the evaluation
on the stability of seafloor area.In this study, the influence
of different cutting direction is discussed. The block is cut by
horizontal and vertical direction to discuss the influence of
cutting direction. As shown in the results, the factor of safety
adopted from the block cutted by horizontal direction is smaller
than the block cutted by vertical direction.In this study, the
influnce of slope angles, water depth and wave height are
discussed. As shown in the results, as seafloor slope angle
increases, the factor of safety would decrease. This shows that,
as the slope angle increases, the seafloor would become
unstable. As shown in the results, the factor of safety would
decrease, as water depth increases. This results show that as
the water depth increases, the load acted on the seafloor would
increase, and thus the seafloor would become unstable.The
results also showed, the factor of safety would decrease, as
wave height increases. This shows that the wave height would
influnce the stability of the seafloor. In order to prove the
capability of this model, the results adopted in this study are
compared with results adopted from STABL5 and BEM. As shown from
the comparison results, the results adopted from the model
proposed in this study, agreed with the results adopted from
STABL5. Comparison are made with BEM to prove the analysis
method on the water pressure. The results show that the results
in this study agree with the results adopted from BEM (Boundary
Element Method). The results for seafloor pore pressure in this
study are compared with Madsen(1978). The results adopted in
this study also agree with the results adopted from
Madsen(1978).A study on the excavated seafloor are also made to
discuss the influence of hydraulic sand fill activity on
seafloor. The results in this study show that DDA is applicable
in marine Geotechnical Engineering field.
| Identifer | oai:union.ndltd.org:TW/084NTOU0192002 |
| Date | January 1996 |
| Creators | Oh, Yan-Nam, 胡淵南 |
| Contributors | Line-Kwei Chien, 簡連貴 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 118 |
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