瓯江二桥主桥墩局部冲刷试验研究

Model test study on local scour about main abutment of Oujiang's second bridge

本文采用系列模型试验方法，对瓯江二桥主桥墩局部冲刷问题进行了研究。试验结果表明主桥墩最大冲刷深度与上游径流量及主桥墩轴线走向有关：对径流为百年一遇洪水流量，主桥墩轴线走向与水流流向一致时，其最大冲刷深度为11．69m；主桥墩纵轴线与流向夹角为20°时，最大冲刷深度为14．81m。试验得到施工围堰局部冲刷与流量的关系，得出最大冲刷深度，并提出围堰局部冲刷的防护措施。

Making use of series model test, the local scour about the 'lain abutment of Oujiang's second bridge were studied. The experiment results show that the maximum scour depth has relation to the runoff and the longitudinal axis trend of main abutment: the maximum scour depth is equal to 11. 69 m when the runoff is equal to 23 400m'/s (the runoff frequency is equal to 1 % ) and the longitudinal axis trend is parallel to the flow direction; it is 14.81 m when the included angle between the axis trend and the flow direction is 20 degree. The local scour and the erosion control measures about construction cofferdam of the main abutment are also studied.