ABSTRACT OF TECHNICAL DISSERTATION

1. PhD candidate: Nguyen Anh Tien

2. The title of the Dissertation: Studying and proposing a solution as well as assessing the function of wave energy reduction of hollow complex dike for coastal protection from Ca Mau cape to Ha Tien.

3. Specialization: Technical Construction of Hydraulic Works; Code: 9 58 02 02

4. Supervisors:            (1). Assoc. Prof. Dr. To Van Thanh

                                      (2). Prof. Dr. Thieu Quang Tuan               

5. Academic training organization: Vietnam Academy for Water resources..

The Dissertation information

6. Research objectives, subject and scope of the study

6.1. Research objectives

Studying and proposing the solution for a wave-attenuating breakwater with a flexible assembly structure by precast fixative concrete structures, appropriate applications to reduce wave energy for protecting the eroded mangrove-mud coast from Ca Mau cape to Ha Tien and developing a semi-experimental formula to calculate and determine the wave transmission coefficient of the construction suitable for the natural conditions in the West Sea of the Mekong Delta.

6.2. The object of the study

The wave-attenuating dike has an innovative structured shape and the mechanism of the wave energy consumption when passing through the construction.

6.3. The scope of the research

Hollow submerged breakwater with additional piles system on the top of submerged dike (complex hollow dike called in the Dissertation), dike built in muddy beaches in front of the eroded mangrove belt from Ca Mau cape to Ha Tien in the Mekong Delta.

7. Research methodology

- General research method.

- Experimental research method on physical modelling combining wave energy theory.

- Method of experts.

- Method of applied research.

8. Scientific and practical signification

The dissertation research has creatively applied between the theory of wave energy balance with experimental study based on physical models to analyze and determine the influence of the basic dominant parameters and develop a method to calculate wave transmission for new and non-traditional wave attenuating breakwaters.

The solution of complex hollow breakwaters quite fully meets the multi-objective criteria of a scientific and technological solution for coastal protection and it is completely feasible when considering practical application for the purpose of wave attenuating to protect the mangrove muddy coast from the erosion from Cape Ca Mau to Ha Tien in the western sea of ​​the Mekong Delta. In particular, the results of the dissertation have been applied to evaluate and select the complex hollow breakwaters (the pilot works of the National Project, the code of ĐTĐL.CN-09/17) in the design function for reducing waves to support for planting coastal mangrove.

9. New contributions of the Dissertation

1- The study proposes a solution for a complex hollow breakwater, which is flexibly assembled by precast concreted structures, alternative to traditional stone poured material. In which, the base block is a hollow submerged breakwater, the dissipation of wave energy through the wave breaking, the friction and currents in the breakwater body, the piles system on top of the submerged breakwater dissipating wave energy based on the drag friction. The novelty and creative level of this structural solution is to propose flexible disposition of the piles system on top of the submerged dike to increase the efficiency of dissipating wave energy from this submerged dike, but incompletely prevent the flow through into the submerged dike. It helps maintain the processes of exchanging water and material inside and outside the breakwater system to minimize negative impacts on the adjacent natural environment. Also, it is capable of sedimentation, supporting the conservation or the restoration of the mangrove ecosystem in the West Sea of ​​the Mekong Delta. The breakwater structure is suitable for the soft muddy geology with the capacity of poor weight load, the fast construction and installation, a reasonable cost, the ability of reuse.

2- Developing the method and establishing the general semi-experimental formula to quantify the wave transmission coefficient of a complex hollow breakwaters in association with the natural conditions of the West Sea region of the Mekong Delta.

See Detail: Summary of Technical Dissertation - NGUYEN ANH TIEN