A Study On The Typhoon Prevention Ability Of Tongzhao Fishery Port In Xiangshan Bay

Our country is one of the countries suffering most from Marine disasters in the world and storm surge disaster is located in the first place.Zhejiang province owns lots of fishery ports,which were perennially affected by the storm surge disaster took a heavy toll on.This situation had intensified in recent years.Therefore,it is of great practical significance to study the Typhoon prevention assessment of fishery ports.To provide useful methods and example to compile Technical directives for typhoon prevention assessment of fishery ports in Zhejiang province,Xiangshan Tongzhao fishery port was valuated in three aspects:the level of shoreline facilities against typhoon,the level of anchorage areas against typhoon and the level of breakwaters against wave.When evaluating the level of shoreline facilities against typhoon,Based on the certified model,the simulated data(water level,depth averaged velocity and significant wave height etc.)were got by using the nested grid wave-flow coupled model.Astronomical tide high tide,the added height of water and the effective wave height were superimposed,and compare the result to the measured shoreline elevation todetermine the corresponding level 13.When evaluating the level of breakwaters against wave,it was considered the main function of the breakwater is cutting waves,so the absolute value of the wave height difference in numerical simulation of the presence and absence of breakwater was regarded as a criterion for judging its anti-wave capability.The corresponding level is 1.15m.In order to facilitate the comprehensive rating assessment,it was proposed to convert the wave height difference to the level of breakwaters against wave,the corresponding level is 15.When evaluating the level of anchorage areas against typhoon,it was proposed to combine macro numerical simulation with micro force analysis for evaluation.After collating and analyzing the materials of fishing boats species,tonnage and dimensions provided by Zhejiang Shipping Bureau,three standard ships were obtained.According to the anchorage coefficient and the chain gripping coefficient of the base,terrain and standard fishing vessel of the Xiangshan port,the anchoring force of the different fishing vessels in the anchorage was got.Put the wind speed and flow velocity obtained by numerical simulation into the recommended formula of Specification for port engineering loads to get the wind load and the flow force under different conditions of sedimentation,Wind angle,and drift angle.Compare the anchor holding power and the external and comprehensive force to determine the corresponding level 16.Erosion and deposition was studied for the breakwater,siltation contour line and the depth of the water were obtained to judge the influence was little enough.Finally the level of Xiangshan Tongzhao fishery port against typhoon was determined as 13 based on the principle of "lower,not higher" which reflected the weakness of the port and 14.85 via weighted average which reflected the true level of the port.