Author(s): Jian Zeng; Zhiyong Zhang; Qiushun Wang
Linked Author(s):
Keywords: Seawall foot scouring; Seawall safety engineering; Design scouring elevation; Zhejiang province
Abstract: Under the influence of extreme hydrodynamic forces, the severe scouring of the riverbed at the seawall foot will lead to the overall instability of the seawall structure, which is one of the main factors causing the damage of the seawall. For the Seawall Safety Engineering in Zhejiang Province, this paper systematically analyzes the scouring characteristics of the seawall foot and research difficulties, studies the method of determining the scouring elevation, puts forward the research ideas and calculation technology system of the design scouring elevation of the seawall foot, and takes the Yuecheng Seawall Safety Engineering in Shaoxing city as an example to carry out demonstration application. The main conclusions are: the strong hydrodynamic force causes severe scouring of the riverbed, the law of erosion/deposition is complex, and the standard of scouring elevation at seawall foot is different, which are the main difficulty in the research of scouring at the seawall foot. The design scouring elevation should be the elevation under the corresponding hydrodynamic conditions of the seawall defense standard. The analysis of measured data, mathematical model calculations, and physical model experiments are effective methods for studying scouring problems. For the curved concave bank section, and complex bank sections affected by wading structures in the estuarine area, the combination of the above three methods should be used to determine the design scouring elevation. The remaining bank sections should be studied using at least two methods: analysis of measured data and mathematical modeling methods. For the Yuecheng seawall, the front water area has strong tidal currents and deep troughs that are close to the bank. The seawall foot is severely eroded and shows an increasing trend, with a measured minimum scouring elevation of -3.24 m. By using research methods such as measured data analysis, mathematical model calculations, and physical model experiments, the flow velocity in the water area in front of the seawall can reach 4.82–6.61 m/s under 300-year dynamic conditions, and the design scouring elevation is -4.0 to -6.0 m, providing key parameters for the design and erosion prevention of the Yuecheng Seawall Safety Engineering.
Year: 2023