黄河兰州新城段的水文泥沙特征对新桥建设的影响

Effect of hydrologic and sediment character of the Yellow River within Xincheng section of Lanzhou on construction of a planned bridge

调查分析兰州市新城黄河大桥所在河段的水文泥沙特征,确定河道按百年一遇流量标准设防,其设计流量为6 500 m3/s,河道平均流速为3.98 m/s,主流冲刷系数P=1.39,河床覆盖层平均颗粒为30 mm。计算了河段主槽与边滩以及各个桥墩的冲刷深度,得出了较为详细的黄河兰州新城段河床演变规律和旧桥桥渡冲刷结果。以上结果可以为即将兴建的新城黄河新桥起到非常宝贵的借鉴作用。

Analyzing the character of hydrologic and silt of Xincheng Yellow River bridge, the stream design discharge is determined to be 6 500 m3/s, stream mean velocity to be 3.98 m/s, scour rate of main current to be 1.39, average grain diameter of bed overburden layer to be 30 mm; and the deep of eroding has been calculated. Thus, more detailed and accurate develop law of the riverbed and erode result are gotten. It should offer a reliable basis and draw a every valuable lesson for constructing a new bridge within this section.