跨河建筑物局部水沙动力数值模型开发与应用

局部河床冲刷是引发桥梁、渡槽等跨河建筑物水毁的重要因素，利用数值模拟方法能够对洪水过程中跨河建筑物的局部冲刷风险进行分析与预测。介绍了一套用于模拟跨河建筑物附近水沙动力过程的数值模型HydroCRS，可计算建筑物所在河流的流场分布、泥沙运动及河床冲淤情况。模型采用一、二维嵌套的方法，在提高计算效率的同时能够较好地对接水文预报模型，以形成从气象预报到水文预报、再到局部冲刷风险预测的完整模拟系统。将模型应用于南水北调中线一期工程总干渠双洎河渡槽段工程的水沙动力过程模拟中，模型能够反映实际复杂地形下河床冲刷特性，为工程实践及风险评估提供参考。

Numerical models of local hydrodynamics and sediment transport around river-crossing structures

Scour around bridge and aqueduct piers is generally considered as a key factor that could probably bring devastating damage to river-crossing structures. Using numerical simulations, we can analyze and forecast the risks caused by such local scours during a flood. This paper describes a system of hydrodynamic and sediment transport models the authors developed, namely HydroCRS, which can be used for calculation of the flow field, sediment transport, and riverbed scour around underwater structures. This model system adopts integration of 1D and 2D models to improve computational efficiency, which also facilitates its connection to hydrological models. Associated with a hydrological model for real-time flood forecasting derived from the weather forecast data, it can achieve the prediction of dangerous scenarios of flows around a river-crossing structure. The model system is applied to simulations of the Shuangji River aqueduct of South-to-North Water Diversion Project, revealing the complicated characteristics of local scour around bridge piers and offering helpful results for the risk management of the aqueduct.