渭河典型河段桥梁群的河道影响研究

Study on River Influence of Bridge Groups in Typical River Section of Weihe River

为研究跨河桥梁对河道产生的不利影响,以渭河下游典型桥梁群河段为研究对象,通过平面二维数学模型分析典型桥梁群对河道水流流向及流速等水力条件、桥前壅水的影响。结果表明,由于各桥位处墩台对河道的束窄作用,桥群河段水位呈现以各桥位为节点的水位壅高、降低的间歇式水位变化,可能对局部河势变化产生影响。桥前壅水高度与桥梁断面压缩比呈线性相关关系,而断面压缩比与桥梁跨距、墩形尺寸密切相关;加大跨距、减小墩形尺寸,是降低断面压缩比及桥前壅水高度的有效途径。相比椭圆形和长方形桥墩,圆形桥墩对桥梁附近流场、河道行洪及桥梁墩台安全的影响相对较小,建议今后桥梁建设中桥墩形式采用圆形为主。结果可为后续跨河项目审批管理提供参考。

In order to study the adverse effects of bridges across the river on the river channel, the typical bridge group in the lower reaches of the Weihe River is taken as the research object. The two-dimensional mathematical model is used to analyze the influence of typical bridge groups on the hydraulic flow conditions such as river flow and velocity, and the waterfront before the bridge.. The results show that due to the narrowing effect of the piers on the bridges at the bridges, the water level of the bridges in the rivers of the bridges is characterized by the high water level and the reduced intermittent water level change with the bridges as nodes, which may affect the local river potential changes. The height of the bridge before the bridge is linearly related to the compression ratio of the bridge section, and the compression ratio of the section is closely related to the span of the bridge and the size of the pier. Increasing the span and reducing the size of the pier is to reduce the compression ratio of the section and the front of the bridge. An effective way of water height. Compared with elliptical and rectangular piers, circular piers have relatively little impact on the flow field near the bridge, river flooding and bridge pier safety. It is suggested that the form of piers in the bridge construction should be circular in the future. The results can provide reference for the subsequent approval management of cross-river projects.