桥墩壅水效应的影响因素与最优桥墩墩型研究

Study on Factors Influencing the Backwater Effect of Bridge Pier andthe Optimal Pier Shape

采用宽水槽物理模型试验方法,研究了水流流速、水深、桥墩轴线与水流夹角、墩型对桥墩壅水效应的影响,并从壅水效应最小的角度,确定了最优桥墩墩型。结果表明,水流流速越大、水深越浅,桥墩壅水效应越强,与水深变化的影响相比,桥墩壅水效应对流速变化的敏感程度更高。基于桥梁工程现状,相关规范要求,以及最新研究成果,选择方墩、流线墩、圆墩三种墩型作为试验墩型开展研究,结果表明,当桥墩轴线与水流夹角在15°以内时,方墩、流线墩、圆墩墩型造成的上游水位壅高值均相对较小,最优墩型为流线墩;桥墩轴线与水流夹角在23°~35°时,最优墩型为流线墩,桥墩轴线与水流夹角大于35°时,最优墩型为圆墩。

By aopting the physical model with the wide flume test,the effects of water flow velocity,water depth,the angle between pier axis and water flow direction,and pier shape on the backwater effect were studied from the perspective of minimizing.The backwater effect,the optimal pier shape with the weakest water resistance under different conditions was confirmed.The study shows that the faster water flow velocity and the shallower water depth,the stronger backwater effect of the pier is.Compared to the influence of water depth changes,the backwater effect of piers is more sensitive to water flow velocity changes.Based on the current status of bridge,relevant specifications requirements,and the latest study results,three shape of piers,namely the rectangular pier,streamline pier and bi-circular pier,are selected as the experimental pier types for study.When the angle between pier axis and water flow direction is less than 15°,the backwater heights caused by square pier,streamline pier and bi-circular pier are relatively low and the optimal shape is the streamline pier.When the angle is between 23°and 35°,the optimal shape is the streamline pier.When the angle is more than 35°,the optimal shape is the bi-circular pier.