环行桩群加承台基础结构的稳定是结构安全运行的基本保障，因此该基础结构的冲刷规律试验研究意义很重要。由于受场地、模型沙选择限制，需要利用系列模型延伸法进行模型试验来研究基础结构海域局部冲刷问题。水流流态表明基础结构尾流旋涡和侧向绕流是影响基础结构冲刷的主要动力。局部冲刷试验表明基础结构局部冲刷部位基本在基础结构两侧和背水面地带，极端高潮位时最大冲刷深度为６．０１ｍ，冲刷深度随水位降低而减少。

Scour tests on annulus pile-group foundation with cushion caps is of great significance since the stability of the foundation essentially guarantees the structural safety. Limited by test site and model sand selection, the model test requires an extension method for series model to study the local scour at the foundation. The flow regime indicates that wake vortex and lateral flow are main influencing factors of scouring. Tests show that local scour generally happens at both sides of the foundation structure and the backside of water. The scour depth reaches its maximum of 6.01m in extreme high mean sea level (MSL) and decreases as the sea level falls.