中文摘要：

针对平原地区河道桥墩壅水问题,采用数值模拟方法,以阻水比α为控制参数,按照产生机制和影响范围的不同,从墩前冲高和桥前壅高两方面考虑桥墩壅水效应。墩前冲高的影响范围由河道断面水位壅高变异系数确定,在高阻水比（α〉7%）情况下,其影响范围相对集中在桥墩附近;对于桥前壅高,以防洪工程中起重要作用的断面平均壅高为表征变量,分析无量纲的相对壅高βyg及最大壅高点距桥墩的相对距离λyg与阻水比之间的关系。结果表明：在高阻水比时,最大壅高位置出现在墩前4～5倍墩宽处,且阻水比的增加会导致桥前最大壅高迅速增大和壅水影响范围的持续扩大;阻水比7%是平原河道桥前水位壅高特性的重要分界点,故大中型桥梁工程的阻水比以不大于7%为宜。

英文摘要：

The backwater caused by bridge piers on plain rivers was numerically simulated using the water-blocking ratio of piers（ α） as the control parameter. The backwater effect of piers was investigated in terms of the creep height in front of piers and the backwater height in front of a bridge according to different generation mechanisms and influence areas.The influence area of the creep height in front of piers was determined by the variation coefficient of the cross-sectional backwater height. It is concentrated around the piers with higher water- blocking ratios（ α 〉7%）. The relationships between the dimensionless relative backwater height βyg,the relative distance from the location with the maximum backwater height to the bridge pier,and the water-blocking ratio were analyzed using the cross-sectional average backwater height as the representation variable. The results show that the maximum backwater height occurs at four to five times the pier width in front of the pier with higher water-blocking ratios,and the increase in the water-blocking ratio causes the maximum backwater height in front of the bridge to rapidly increase and the backwater area to continuously enlarge. The water-blocking ratio of 7% is a significant demarcation value for the backwater height in front of bridges on plain rivers. Thus,the water-blocking ratio of medium and large bridges should not be more than 7%.