海中输电塔塔基附近海床冲刷深度和床面高程是输电塔桩基础设计的重要依据。针对舟山大跨越输电工程，采用海域实测地形资料分析了其海床自然冲刷，利用水槽正态模型试验研究塔基附近的一般冲刷和局部冲刷。研究表明，塔基所处海域海床基本稳定，冲淤幅度很小，多年最大冲淤变幅 0.8 m，塔基处最大局部冲刷幅度为7.5 m。据此，可得塔基附近海床的总体冲刷幅度和设计高程，可为大跨越输电工程塔基冲刷提供参考。

The seabed-scour depth and the seabed elevation around the foundation of the offshore transmission tower are of great importance to the design of transmission towers and poles. Based on the Zhoushan long span power transmission project, this paper analyses natural scour according to measured submarine topography data, and researches on commonly scour and local scour around the foundation of the offshore transmission tower with a channel test under normal model. The study proves that the seabed condition is steady; the maximum amplitude of scour and silting for many years is 0.8 m, and the maximum local scour depth around the foundation of the offshore transmission tower is 7.5 m. On this basis, the total scour and the design elevation can be got, which provides reference for similar long span projects.