| With the continuous development of port economy,the exploitation of the ocean engineering strengthening makes the waters surrounding its hydrodynamic environment change obviously.The wide range of engineering construction for a long period of time in Yangshan deepwater harbor in Shanghai,not only significantly changed the yangshan ocean underwater topography and coastline of conditions,such as the propagation of wave port and adjacent waters,and has significant impact on wave field distribution characteristic and change rule also.Yangshan sea was suffered by several typhoon attacks in history,the typhoon wave distribution and dissemination was certainly impact by the construction.Therefore,it is great significance to study the wave propagation process and wave field distribution characteristics and the variation law of Yangshan Deepwater Port before and after the construction of this sea area under different conditions,the future operation and maintenance,and the engineering safety analysis.In this paper,it was used the measured data of Yangshan sea area in the past 20 years,and analyzed the characteristics of measured wave in Yangshan Sea Area from 1998 to 2002(before Yangshan Project Construction)and from 2003 to 2012(after Yangshan project construction).The MIKE21 SW wave model is used to simulate the situation of the wave field in the early stage of the construction of Yangshan deepwater port and the typical recurrence period of Yangshan period.At the same time,a large number of typhoon data was compared and analysed,that will affect the Yangshan sea typhoon is classify as "landing type" and "steering",the use of MIKE21 SW wave model simulation of two typical path(landing typhoon "Matsa",steering typhoon and the influence of the construction of Yangshan project on the typhoon wave field caused by typhoon in different paths.The influence of Yangshan project on the typhoon wave field of different typhoon is analyzed.The main contents of the above,the conclusion is as follows: After the construction of Yangshan Deepwater Port,the often and strong waves direction changed significantly.At present,the strong wave direction of Yangshan sea area is changed from NE direction to SE direction,NE direction wave in the port area is reduced the most obvious in a return period of 50 years,SE direction wave on had a greater impact in the current stage of the project in a return period of 50 years.Under extreme weather conditions,construction projects can well reduce port "steering type" path of the typhoon,but the " landing type" path of the typhoon had a greater impact on current stage of the project.(1)After the construction of Yangshan Deepwater Port,the occurrence rate of harbor wave in the harbor area decreased from 15% before the project to 3.0%,which was smaller.NE,NNE to the Chung-type has disappeared,the addition of the southeast to the incoming.After the construction of the project,the frequency of NW and NNW increased from 8.9% to 15.3%,and the frequency of NNE and NE was significantly reduced.Added constant wave to SE and NW.After the construction of the project,the average wave period in the port area and adjacent waters increased,and the average period above 4.0s increased from 2.4% before the project to 3.2% after the project.The long period mainly appears in the strong wave up,for SE ~ S and NW ~ NNW.(2)After the construction of Yangshan deepwater port for nearly ten years,the most influential incident wave is SE direction,followed by E direction,NE direction,NW direction and S direction.The construction of Yangshan project makes the NE area in the 50 years,and the wave height is reduced by 2m and the wave velocity is reduced by 1.5m / s.The SE has the greatest impact on the port area and the wave height is 2.5m ~ 3m.NE,E,NW to 50 years after a wave into the port area after the harbor area effective wave height and cycle have different degrees of reduction.(3)There are two types of typhoon paths that produce large typhoon waves in Yangshan harbor area and adjacent sea area.One is the "landing type" typhoon landing from northern Fujian to Zhejiang coast,and the other is in the east or northeast of the "steering" typhoon.The typical typhoon "Matsa" makes the effective wave height of the port area reach 2 ~ 3.5m,and the period can reach 4 ~ 5s.The typhoon generated by the typhoon has a great impact on the wave field in the Yangshan harbor area.Due to the construction of the North Island chain project and the blocking of the branch,the "peak" of the "steering" typhoon "Wei-mao" in the Yangshan sea area has the greatest impact on the peak value of the JONSWAP wave spectrum 61.2% and 59.4%. |
