沙质海岸港口工程上下游岸滩演变模拟敏感性参数研究

Study on sensitivity parameters for numerical simulation of upstream and downstream evolution of harbor engineering in sandy coast

实现沙质海岸港口工程上下游岸滩演变的准确模拟,对解决港口防淤减淤和未来发展空间问题具有重要意义。以毛里塔尼亚A港工程为例,采用Delft3D数值模拟软件,建立了沙质海岸岸滩演变数学模型,对地貌加速因子、边界条件和模型计算范围进行了敏感性分析。研究结果表明,地貌加速因子可取10,既保证模型计算精度和稳定性,也可提高模型计算效率;采用Delft3D进行数模计算时,可采用潮位-纽曼组合边界条件,保证模型边界稳定,并符合现场沿岸泥沙运动和岸滩演变特征;模型计算范围可采用上下游各10 km,既考虑工程对沿岸输沙和岸滩冲淤的影响范围,也保证模型计算效率。开展沙质海岸港口工程相关数值模拟研究工作时,可初步采用上述设置条件。

It is of great significance to realize the accurate simulation of the upstream and downstream sandy coastal evolution of harbor engineering to solve the problems of siltation prevention and reduction and the future development space of harbors.Taking Mauritania Port A as an example, Delft3D software is used to establish a numerical model of sandy coastal evolution.The model focuses on the sensitivity analysis of geomorphic acceleration factors, boundary conditions and the model ranges. The results show that the geomorphic acceleration factor should be 10, which ensures the accuracy and stability of the model, and increases modelling efficiency. When Delft3D is used for numerical modelling, tidal level and Newman combined boundary conditions should be used to ensure the boundary stability, and this kind of boundary conditions conforms to the characteristics of longshore sediment transport and coastal evolution in the field. The model range can be 10 km for both upstream and downstream, which considers the influence range of the harbor on longshore sediment transport and coastal erosion and depositon, and ensures the modelling efficiency. The above setting conditions can be initially adopted in the study of numerical modelling in the sandy coastal harbor projects.