中文摘要：

洋口港LNG码头栈桥工程位于西太阳沙人工岛东北侧海域,水流条件复杂,海床泥沙活动性强,LNG栈桥建成后沿程桩基周围即产生不同规模的冲刷坑.通过对比栈桥建设前后海床地形变化,分析了桩基冲刷坑形成、发展过程.结合工程海域水沙动力环境,阐明了桩基冲刷坑分布规律、原因,总结出强潮流粉沙质海岸工程建设所引起的局部冲刷一般规律.研究结果表明：LNG栈桥沿程桩基冲刷形态分布与涨、落潮优势密切相关,而冲刷范围与强度则受流速大小和桩基规模的影响.冲刷坑早期发展迅速,在平面形态基本稳定后仍有进一步冲深的可能,应采取适当的工程护底防护措施.

英文摘要：

The Yangkou liquefied natural gas（LNG）station is located on the northeastern side of Xitaiyangsha artificial island.With complicated dynamic condition and active sediment,the local scour around the piers has been found after completion.The evolution process is discussed,comparing with the topographical change along the trestle.Considering the hydrodynamic and sediment conditions,the distribution of local scour and the cause are analyzed in the study.The research results show that：（1）the distribution of scour pits is related to the dominant current;and（2）the extent and depth of scour is controlled by the current speed and the scale of piers.After speedy development in short time,the distribution would be stabilized,but the depth of scour pits would be increased.It is necessary to take protection measures around piers in emergency situation.