波流共同作用下反斜桩局部冲刷特性试验研究

在波流环境中，反斜桩周围的涡流结构及波浪传播特性与垂直桩存在较大差异，进而影响到桩基局部冲刷进程。为了解波流共同作用下反斜桩局部冲刷特性，在波流水槽中针对不同倾角的反斜桩开展了局部冲刷试验，初步探究了局部冲深历时特性、影响因素及床面形态特征。研究结果表明:在清水冲刷条件下，反斜桩局部冲刷深度始终小于垂直桩; 当桩身倾角增加时，平衡冲刷深度逐渐减小，相对时间尺度逐渐增大; 冲刷坑宽度相对垂直桩更小，呈现“水滴状”形态，尾后沙丘呈现出更长的单峰“带状”结构，不规则性较为突出; 局部冲深与弗劳德数之间存在着较高的相关性，但向上游倾角产生的波浪变形效应使得冲刷深度与流速比和Keulegan-Carpenter数的具体函数关系更难以确定。

Experimental study on local scour characteristics around an upstream inclined pile under combined wave and current action

In the context of wave-current, the characteristics of vortex structure and wave propagation around the upstream inclined pile differ significantly than around the vertical pile, which affects the local scour process of the pile foundation. To better understand the characteristic of local scour around upstream inclined piles under the joint action of wave and current, local scour tests were carried out in the wave-current flume for the upstream inclined piles with different inclination angles. Besides, a preliminary investigation was conducted into the ephemeral characteristics of local scour depth, influencing factors, and the characteristics of bed morphology. As suggested by the research results, the local scour depth of upstream inclined piles is smaller compared to vertical piles under the context of clear water scour at all times. The equilibrium scour depth decreases progressively, and the relative time scale (T₀*)shows an incremental increase when the pile inclination rises. Besides, the width of scour hole is smaller compared to vertical piles, showing a teardrop-like shape, while the dune after the tail exhibits a longer single-peaked band structure with a more significant irregularity. Despite a close correlation between the depth of local scour and Froude number, the wave deformation caused by upstream inclination makes it more difficult to determine the specific function of scour depth, radio of velocities and Keulegan-Carpenter number.