Experimental investigation of local scour around complex bridge pier of sea-crossing bridge under tidal currents
Experimental investigation of local scour around complex bridge pier of sea-crossing bridge under tidal currents
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DOI：
10.1016/j.oceaneng.2023.116374
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发表时间：
2023-12
影响因子：
5
通讯作者：
Peng Yu;Jiuchao Chen;Jiale Zhou;Jiang Li;Lie Yu
中科院分区：
文献类型：
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作者：
Peng Yu;Jiuchao Chen;Jiale Zhou;Jiang Li;Lie Yu
为研究潮流作用下大型复杂桥墩周围局部冲刷过程，以港珠澳大桥群桩承台为原型进行了局部冲刷试验。对桥址的地质条件进行了探索，并对取样的土壤进行了实验分析，以确定模型砂。根据桥址潮流的长期观测资料，对潮流进行调和分析，得到桥址潮流的水动力特征。在此基础上，进行了潮流作用下大型群桩周围局部冲刷的水槽试验。研究结果表明，港珠澳大桥站场潮流流速具有落潮流速大于涨潮流速的特点。在N和S方向上的流动方向的频率更显著。桥址潮流属不规则半日潮。潮流作用下的最大冲刷深度出现在涨、落潮过程中流速最大的一侧，其值略小于单向流作用下的冲刷深度。潮流作用下的平衡冲刷持续时间比单向水流作用下的长。潮流作用下的平衡冲坑形状由上游侧的圆弧形变为端深中浅的马鞍形，并在涨、落潮两端形成较单向流情况更长的淤积区。桩基础的尺寸和布置对实现平衡冲刷的冲刷坑的形状具有显著影响。
To study the process of local scour around the large-scale complex bridge pier under tidal currents, local scour experiments were carried out using the pile group-cap of the Hong Kong-Zhuhai-Macao Bridge (HZMB) as prototypes. The geological conditions at the bridge site were explored and the sampled soil was experimentally analyzed to determine the model sand. Based on the long-term observation data of tidal currents at the bridge site, a harmonic analysis of tidal currents was conducted to obtain the hydrodynamic characteristics of the tidal currents. Then a flume experiment of local scour around the large-scale pile groups under tidal currents was carried out. Research results indicate that the tidal currents velocity at the HZMB site exhibits the characteristic that the falling tide velocity is greater than the rising tide velocity. The frequency of the flow direction in the N and S directions is more significant. The tidal currents at the bridge site belong to the irregular semi-diurnal tide. The maximum depth of scour under tidal currents occurs on the side with highest velocity in the rising and falling tide process, and its value is slightly lower than the value under unidirectional flow. The duration of equilibrium scour under tidal currents is longer than under unidirectional flow. The shape of the equilibrium scour pit under tidal currents has changed from a circular arc shape on the upstream side to a saddle shape with deep ends and shallow middle, and has formed a longer sedimentation zone at both ends of the rising and falling tides compared to the situation under unidirectional flow. The size and layout of the pile foundation have a significant impact on the shape of the scour pits that achieve equilibrium scour.