水-冰-沙耦合作用机制下河冰运动与岸滩侵蚀研究

北方河流的岸滩侵蚀主要集中在冬季和春初，与河冰影响密切相关。河冰运动与岸滩侵蚀过程中的水-冰-沙耦合作用机理是河冰水力学研究的热点和前沿，如何量化河冰对床面侵蚀、岸滩崩塌及失稳土体的影响是其难点。. 本项目立足上述前沿科学问题和我国北方河流治理的实践需求，以理论分析、数值模拟和机理实验为关键支撑，研究建立耦合水流变化、河冰运动、泥沙输移和岸滩侵蚀的二维数学模型，创新利用光滑粒子法计算河冰对岸滩的刮擦作用力,并尝试以双泥沙休止角法判断不同含水层岸坡的稳定性，研究冰塞过程对河床冲淤的影响，分析河冰影响下的岸滩侵蚀、崩塌和再平衡动态过程，进而揭示出水-冰-沙互馈机制下的河冰运动与岸滩侵蚀规律，明晰河流输冰与岸滩演变间的动平衡机理，为科学认知河冰刮擦对河流岸滩侵蚀促进的物理过程提供依据，并进一步支撑黄河等寒区河流的防凌减灾实践。

Riverbank retreat occurs frequently in winter periods or early spring in the Northern rivers. Such bank retreat is correlated with the river ice influence. It is one of the hottest research topics in river ice to investigate flow-ice-sand coupling mechanics in river ice movement and riverbank retreat. The key scientific question is how to evaluate the river ice influence on riverbed scouring, riverbank collapses and re-distribution of waste mass. . Based on the hot research topic and engineering requirements for the protection of cold region rivers, this proposal focuses on the interaction and feedback between flow dynamics, ice movement, sediment transport and riverbank erosion. With the support of theoretical analysis, numerical modeling, and flume experiments, it will build a two-dimensional dynamic river ice model coupling river flows, ice dynamics, sediment movement and riverbank evolution. The primary novelty of the model is using the smoothed particle hydrodynamics method for estimating ice gouging and abrasion on riverbanks. The model is capable of evaluating bank surface stability and analyzing the re-stabilized bank slope using two repose angles for different soil layers. It expands our ability in evaluating flow-ice-sand interaction by considering river ice influence on classical flow and sediment transport problems. The study improves our understanding of dynamic equilibrium processes between the river ice transport and riverbank evolution. It contributes to the wintertime river management and ice flooding prevention in Yellow River by providing theoretical understanding on scientific fundamentals and numerical modeling methods.