跨海桥梁基础冲刷特征研究

在我国近海海域，跨海桥梁基础冲刷是影响大桥安全的重要因素之一。基于金塘大桥2014、2015和2017年桥墩基础冲刷实测资料，并结合建桥前地形测验资料进行了案例分析，解析出了往复潮流条件下桥墩基础的一般冲刷及局部冲刷深度，金塘大桥中引桥桥墩一般冲刷深度为3.3~3.6 m，平均局部冲刷深度约8.3 m。往复潮流条件下桥墩基础局部冲刷坑受双向潮流影响向上下游延伸，形状呈椭圆形，各墩冲刷坑纵向长度与最大局部冲刷深度呈近似线性关系，长度约为局部冲刷深度的10~12倍，而各墩冲刷坑横向宽度则基本一致，约为桥墩基础宽度的4~5倍，与最大局部冲刷深度无明显相关性。跨海桥梁基础冲刷深度计算方法及冲刷坑形态特征的研究成果可供跨海大桥基础设计、运行维护及基础冲刷防护参考。

Scour features of sea-crossing bridge piers

The local scour around bridge piers is one of the main safety influence factors of sea-crossing bridges in the nearshore region. Based on the survey data of six bridge piers of Jintang Sea-Crossing Bridge in Hangzhou Bay during 2014, 2015 and 2017, the scour effects around the bridge piers under bidirectional tidal flows were systematically studied. The general scour depth and the maximum local scour depth were analyzed respectively. It is found that the general scour depth is about 3.3~3.6 m, while the average local scour depth is about 8.3 m. The local scour holes extend in both upstream and downstream directions with elliptic shapes due to bidirectional tidal flows. The longitudinal length of scour hole is approximately linear with the maximum local scour depth with a ratio of about 10~12. While the scour hole width of each bridge pier is nearly the same, about 4~5 times the pier width. In addition, there is no obvious correlation between the width of scour hole and the maximum local scour depth. The research results about scour depth prediction and scour profile characteristics can provide a reference for sea-crossing bridge foundation design, maintenance and scour protection.