浙江省的感潮河口水闸众多，其闸下软基防冲是众人最关心的问题。结合南台头排涝闸工程的水工模型试验和原型的实际运行情况，对闸下口门区流态及冲刷情况进行分析。结果表明：利用起动流速相似准则选择天然沙模拟闸下软基，能较好地反映实际情况；对于因冲刷而易发生河床演变的工程，需通过动床试验来论证。该成果可供类似工程参考。

There are many sluices built in tidal estuary, Zhejiang province, in which an important problem is scour protection for soft foundation of sluice downstream. By the study of hydraulic model test and prototype observation, the results show that to select natural sediment with the similarity law of strarting velocity to simulate the soft foundation of sluice downstream can reflect the practical condition, and that it is necessary to adopt the movable－ bed model for a project, which easy occurs fluival process caused by eroding. This results can be used for reference to analogous engineering.