施工期强越浪作用下围区板桩墙预留龙口局部冲刷研究

Local scour study of reserved closure gap in sheet-pile wall of surrounding areaunder strong overtopping waves during construction period

龙口位置属于流速骤然增大区且流场复杂,准确预测冲刷形态对龙口结构设计和安全运行具有重要意义。依托海外某大型围海造陆港口工程,借助CFD软件,对施工期强越浪作用下不同结构龙口局部冲刷特点进行了三维数值计算,得到了龙口周围流场分布规律和局部冲刷形态,对冲刷防护提出了针对性建议。结果表明:龙口周围流场复杂但存在一定规律,其特点与龙口局部冲刷因素存在一定对应关系。龙口区域设置挡砂结构,其下方存在淘刷风险,易形成冲刷通道,发展到一定程度,将扰乱龙口后方原有流场,加剧龙口底部和后方的冲刷程度。

The location of the closure gap belongs to the area where the velocity increases suddenly and the flow field is complex,so it is of great significance to accurately predict the scour pattern for the structural design and safe operation of closure gap.Relying on a large-scale overseas reclamation port project,with the aid of CFD software,we carried out the 3D numerical calculation of local scour characteristics of closure gap of different structures under strong overtopping waves during the construction period,and obtained the distribution regularities of flow field and local scour pattern around closure gap respectively,thus provided some suggestions on erosion protection.The results show that the flow field around closure gap is complex,but there is a certain law,and its characteristics have a certain corresponding relationship with the local scour factors of the closure gap.If a sand retaining structure is set in the closure gap area,there is a risk of scouring below it,which is easy to form a scouring channel.When scour develops to a certain extent,it will disturb the original flow field behind the closure gap and aggravate the scour degree at the bottom and back of the closure gap.