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为了探明黄河下游在役桥梁群桩基础的冲刷特性,对郑州刘江黄河公路大桥群桩基础进行了冲刷深度测试。测试结果表明:黄河河道展宽作用使得黄河水流对桥梁群桩基础的冲刷主要表现在侧向冲蚀,而非河道处为垂直向下冲刷,导致跨黄河桥梁群桩基础局部冲刷坑最大深度位置并没有全部出现在群桩迎水侧前方,而是部分出现在顺水流方向的侧面;黄河水流对跨黄河桥梁群桩基础冲刷作用最强烈的位置并不是主河道水深最深或水流流量最大的位置,而是在主河道两侧的位置;一般情况下,在顺水流方向,跨黄河桥梁群桩基础迎水侧冲刷深度大于背水侧,迎水侧的冲刷坑坑壁坡度较背水侧陡;群桩基础冲刷坑边缘大多数在距承台2.25倍桩径处;河道转弯对河床冲刷的影响较大,转弯外侧的河床冲刷更为严重,建议在设计中适当增大河道转弯外侧桩基的最大设计冲刷深度。
In order to find out the scouring characteristics of the pile foundation of the bridge group in service of the lower Yellow River, the pile foundation of Zhengzhou Liujiang Yellow River Bridge was tested for the scour depth. The test results show that the widening effect of the Yellow River channel makes the scour of the Yellow River water flow to the pile group foundation of the bridge mainly in lateral erosion instead of vertical downward scour, resulting in the maximum depth position of partial scouring pits across the Yellow River Bridge group pile foundation Not all of them appear in front of the water front of the pile groups, but some of them appear on the side of the cis-flow direction. The strongest role of the Yellow River water in scouring the pile foundation across the Yellow River Bridge group is not the deepest water depth or the largest water flow in the main channel, But on both sides of the main channel; under normal circumstances, in the direction of water flow, the scouring depth on the water embankment of the pile foundation crossing the Yellow River Bridge Group is greater than that on the backwater side, and the gradient of scour pit on the water-facing side is steeper than that on the backwater side; Most of the edge of the foundation scour pit is located at 2.25 times of pile diameter away from the platform. The river bend has a great influence on the river bed scour and the riverbed erosion on the outside of the bend is more serious. It is suggested that the maximum design of the pile outside the curve bend be appropriately increased Scour depth.