基于防洪安全的北京市城市河道清淤阈值研究

Study on dredging threshold of Beijing urban river on flood control

河道淤积会导致河道过水断面减小、行洪能力降低,严重威胁河道的行洪安全。清淤阈值确定方法的研究与推广,对科学开展城市河道清淤工作具有重要意义。基于清河、通惠河一维水动力学模型,模拟分析了不同淤积厚度对河道行洪水位的影响,进而推求城市河道淤积厚度与行洪水位抬升关系的经验公式,用于确定河道清淤阈值。将经验公式应用于凉水河重点河段与温榆河一般河段,计算清淤周期分别为5 a和14 a,与数值模拟结果基本一致。经分析论证经验公式具有较高的实用性与可靠性,可用于城市河道清淤阈值的确定。

River sedimentation will decrease the river's cross-section area,and in turn,decreases the flood convey⁃ing capacity and threatens the safety of the river's flood discharge seriously.The research and popularization of the determination method of dredging threshold is of important significance to urban river dredging.Based on the one-dimensional hydrodynamic model of the Qinghe River and Tonghui River,the effects of different silting thickness on the flood water level of the river channel are simulated and analyzed,and the empirical formulation of the relationship between the silting thickness and the rise of flood water level of the urban river is deduced,which can be used to determine the dredging threshold of the river channel.By applying the empirical formula to the critical section of the Liangshui River and general section of the Wenyu River,the calculated dredging cycles are 5 and 14 years,respectively;which are basically consistent with the numerical simulation results.The empirical formula is proved to be practical and reliable and can be widely used in the dredging threshold determination in urban river.