桥墩对周围海域水动力环境影响研究

Impact of Bridge Piers upon Hydrodynamic Environment in Surrounding Seas

建设在海岸河口水域的大桥桥墩,会增加桥位水域的阻力并减小过水断面,从而对周围海区的水动力环境产生一定影响,而海岸河口水动力较为复杂,单纯采用某一种研究手段往往难以全面地分析这种影响。文章以浙江省温州市大门大桥为例,通过对大桥所在的大、小门岛和沙头水道海域的水动力条件、泥沙条件及地形冲淤变化进行分析,掌握了该海域的水文泥沙环境与冲淤演变规律,对大桥建设后地形演变趋势进行了预测;然后又建立了二维潮流场数学模型,模拟研究大桥建设对周围海区的潮位、水流、潮量等水动力环境的影响。结果表明:工程建成后,工程对周围海域水动力环境影响仅在桥位附近,不会引起其他水道和海域的改变。

Bridge piers built in estuaries will increase the drag force of flow and decrease the cross section of flow, thus producing impact upon the hydrodynamic conditions in the sea area where bridges are built. However, as the hydrodynamic conditions in estuaries are complex, it is difficult to analyze completely the impact caused by bridge piers just with one method. Taking Damen Bridge in Wenzhou, Zhejiang Province, as an example, the paper makes a prediction of the trend of evolution of the landform after the completion of the bridge on the basis of the hydrological and sediment conditions and the evolution pattern of alleviation known from the analyses of the hydrodynamic conditions, bedload conditions and fluvial process near Damen and Xiaomen Islands and in Shatou Waterways. Furthermore, a two dimensional hydrodynamic numerical model was developed to study the impact of the construction of the bridge upon the hydrodynamic conditions of tidal level, flow velocity and tidal flow in the surrounding seas. The results showed that, after the completion of the bridge, the impact of the bridge piers upon the hydrodynamic environment in the surrounding seas is only shown near location where the bridge is built and will not cause the change of the waterways and the surrounding sea area.