舟山渔港风暴潮模拟分析

Simulation and analysis of storm surge at Zhoushan fishing port

渔港风暴潮研究对防灾减灾具有重要意义。本文构建了舟山海域嵌套网格的风暴潮模型,经天文潮与风暴潮实测资料验证效果良好。设计5个方向共14条台风路径,计算了2017年8月8−12日大潮期12~17级台风下舟山渔港的风暴潮位。结果表明,由于向岸风作用南侧SE向比北侧E向登陆台风所造成的最高风暴潮位高35.7%,差值可达82 cm;对于两端通海的舟山渔港,南侧0.5R处登陆的SE向台风,风向与东口门朝向一致而跟渔港走向斜交,有利于水体进入并滞留,此时风暴潮位最高。南侧12级台风下ESE、SE、SSE发生漫堤,而北侧登陆台风无漫堤风险,沉降等原因造成海堤防台能力两头低于中段;数值试验显示,若在小干岛东侧设置丁坝,可将17级台风作用下的漫堤概率由26.23%减为10.66%。

There is a great significance to study the storm surge in the disaster prevention and mitigation of fishing port. This paper constructs a storm surge numerical model with the nested gird at Zhoushan fishing port, and the calculated results of astronomical tide and storm tide are in a good agreement with the practice. Fourteen typhoon paths in 5 directions are designed, and the storm tide level of Zhoushan fishing port is calculated under the typhoon of 12-17 level during the great tide period of August 8-12, 2017. The results show that storm tide peak in SE path on the south side is 35.7% higher than the north E path due to the effect of the shore wind, and the difference can reach 82 cm.The Zhoushan fishing port passes through sea at both ends, and the wind direction is consistent with the east exit door and oblique to the fishing port at 0.5 R SE path on the south side typhoon, which is beneficial to the water entering and staying. At this time, the storm tidal level is the highest. The 12 typhoon level of ESE, SE and SSE paths on the south side causes overflow. There is no risk of typhoon landing on the north side, and because of the settlement and other reasons, the seawalls’ defense capacities of two sides are lower than the middle section. According to numerical experiments, when a spur dike is installed on the east side of Xiaogan Island, the probability of overflow under the situation of the 17 typhoon level can be reduced from 26.23% to 10.66%.