长江下游河段桥墩压缩冲刷预测研究

Predictionof bridge pier compression scour in lower reaches of Yangtze River

  • 摘要: 建桥引起的河床变化可分为压缩冲刷和局部冲刷。相比于局部冲刷,压缩冲刷研究较少,压缩冲刷使桥址断面产生整体性下降,不利于桥墩基础安全。在总结前人研究成果基础上,以长江下游世业洲桥位方案为例,建立了桥墩压缩冲刷预测模型。探讨了不同空间尺度下桥墩边界的处理方法; 针对长江下游河段水沙特点,从工程安全角度出发,提出了水沙过程的选取方法; 最后预测了桥位上下游河床变形和桥墩压缩冲刷深度,并与长江下游已建桥址断面冲刷深度进行比对,两者基本相当。结果表明, 文中确定的桥墩压缩冲刷是合理的,可为桥墩基础埋深提供技术依据。

     

    Abstract: The riverbed variation caused by the construction of bridges can be divided into the compression scour and local scour. Compared with the local scour, there are few studies on the compression scour. The compression scour makes the section of the bridge site decline integrally, which is adverse to the safety of the bridge pier foundation. On the basis of the summary of the findings given by the previous studies, taking the bridge location scheme of Shiyezhou at the lower reaches of the Yangtze River as an example, a prediction model for bridge pier compression scour is established in this study. Firstly, the treatment methods for the bridge pier boundaries under different spatial scales have been explored. Secondly, from the point of view of engineering safety, the selection method of the water-sediment process is put forward for analyzing the water and sediment characteristics in the lower reaches of the Yangtze River. Finally, the river channel process and the pier compression scour depth in the upstream and downstream of the bridge location are predicted, and compared with the scouring depth of the cross section of the existing bridge site in the lower reaches of the Yangtze River, showing that they are basically the same. The simulated results show that the compression scour of the bridge piers determined by the above methods is reasonable, thus providing a technical basis for the buried depth of the pier foundation.

     

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