一、我国渔港建设现状和发展趋势 我国是世界渔业大国,也是海洋大国,海洋国土面积约为300万平方公里,海岸线总长度3.2万公里(大陆岸线1.8万公里),自北至南分布有黄海北部、辽东湾、渤海湾、莱州湾、烟威、连青石、海州湾、吕四、舟山、温台、闽东、闽南、粤东、珠江口、粤西、北部湾和西南中沙等17个主要渔场.据统计,截止2018年,我国拥有海洋渔业乡392个,海洋渔业村3500个,海洋渔业人口550.93万人,拥有海洋机动渔船23.31万艘,各级各类沿海渔港1292个(2016年农业部渔港调查数据),我国渔港分布地区情况如图1.

In recent years, due to various environmental problems and resource conflicts in coastal areas, nearshore mariculture in China has been increasingly confronted with the severe challenge of space compression. However, in more exposed sea areas with the depth exceeds 20 m, the water quality is much better and the water utilization rate is much lower, less than 1%. With the development of aquaculture technology and equipment engineering, it is an inevitable trend for fish farms to transfer to offshore areas. To reduce the risk of fish farming in open sea areas with strong waves and current, offshore fish farm that having the distinct advantages with moderlization of culture and management were encouraged to develop in the past two years in China. Generally, offshore farm was considered as an integrated farming system composed of cultured fish, floating structure, automatic equipments, various facilities, which was expected to play a positive role in leading and promoting the offshore aquaculture industry. In this study, we conducted a series of physical model tests for a semi-submersible offshore fish farm called "Dehai No.1" in waves, in which the model scale was set as 1:30 and the scale of 1:1 was set for the net mesh size. The "Dehai No.1" offshore fish farm with truss structure was co-designed by South China Sea Fisheries Research Institute and Tianjin De-Sai Environmental Protection Technology Co.,Ltd in the year of 2018. The main experimental parameters of the offshore farm were as follows: length 3.04 m, width 0.92 m, height 0.34 m, designed draft of 0.22 m, no-load weight of 15.33 kg. Considering the actual production requirements, three kinds of single point mooring systems (L=2.67, L=5.34 or L=5.34 plus GW=200 g) and three kinds of ballast status (no-load, half-load or full-load) as well as different regular waves conditions (H=16.7-23.3 cm, T=1.64-2.01 s) were set as the test conditions for the fish farm. Through physical model experiments, the dynamic behaviour of the fish farm under different conditions were studied, and the results of mooring force and motion response were given and compared. Owing to the characteristics of the single point mooring system, the fish farm in practice inevitably drift within the scope of sea area in the center of mooring point on seabed with the variation of low-to-high water surface, studying the sway and surge as well as yaw for the fish farm could not testify its good stability. Therefore, we chose the heave, pitch and roll for analyzing the motion characteristics of the fish farm. The experimental results showed that the single-point mooring system with anchor chain length of 5.34 m and a weight of 200 g could better reduce the mooring force of the fish farm in waves. Among all of the wave conditions, the peak value of each movement component of the fish farm was relatively small. When the fish farm was subjected to the sea loads with wave height of 23.3 cm (7 m in full-scale) and wave period of 2.01 s (11 s in full-scale), the peak value for the heave, pitch and roll was 4.21 cm, 6.55° and 1.19°, respectively, which indicated that the fish farm had good performance for the stability of floating state. Comparing the maximum motion and mooring force of the fish farm under various floating conditions, including no-load and half-load as well as full-load, we found that, in the full-load floating state, the peak value for the mooring force, pitch and roll was biggest, but the peak value of the heave was biggest under the no-load floating state for the fish farm. With increasing wave height, both of the mooring force and motion of the fish farm became larger. The results provide a basis for further understanding the dynamic characteristics of fish farm, and help to provide theoretical and data reference for the structure design and installation of fish farm.

波流力是浅海牧场式围栏设施中柱桩所受的主要荷载,直接影响着桩基的型式和断面尺寸.文章结合椒江大陈岛海域大型浅海牧场式围栏设施工程设计需求,分别采用目前常用的两种柱桩波流力计算方法计算了不同波浪和水流条件下最大总波流力和总波流力矩,结果表明,两者均随波高和流速的增大而增大,而受平均周期的影响较小.同时,相比于波高和平均周期,流速对两种方法计算结果差异的影响更为显著,随着流速的逐渐增大,其差异也逐渐增大.文章研究结果对今后浅海围栏设施中柱桩工程设计的方法选择和科学研究具有一定的参考价值.

2014年11月16至29日,农业部组团赴日本参加现代农业工程标准化建设培训,期间与日本渔港渔场综合研究所第一调查研究部进行了交流,实地考察了静冈县沼津渔港,并收集了日本渔港建设基本方针和建设规划等相关资料.

通过推算影响工程海域的天气过程,得到工程海域-10m水深处不同重现期设计波要素,然后采用Mike21-BW波浪数学模型,对防波堤布置方案和港内波况进行了计算.结果表明:工程受SW、W和NW向风浪影响较大,外海波浪传播至防波堤和护岸位置处,并无明显衰减,防波堤对港内掩护效果较好;北防波堤的建设十分必要,可显著阻挡NW向波浪,明显改善港内泊稳条件.

我国是受台风袭击最多的国家之一,近年来呈现登陆早、密度高、风力强、变化多、破坏力大的趋势,不但给渔船、渔港、养殖设施等造成比较大的损失,还对渔民人身安全造成严重威胁.如2006年的台风"桑美",中心最大风力达到17级,造成148名渔民死亡,952艘渔船沉没;2008年的台风"黑格比"损坏上千艘渔船,使广东、广西局部地区的海洋渔业遭受巨大损失. 截至2010年,国家共投资建设了55个中心渔港、56个一级渔港,渔港综合防风水平提升到10级,可满足近8万艘海洋捕捞渔船在10级以下(含10级)大风天气时的就近分散避风和休渔期停泊,但是还远远无法满足渔船分散避台的需要.考虑到东南沿海区,极端天气灾害频率和强度增大,强台风、超强台风一旦袭击渔船重点集中区和重要渔业生产区,将会对渔业的安全生产造成严重影响,《全国渔港建设"十二五"规划》提出"十二五"期间,在上述区域选择具有天然掩护屏障的、可有效避台的传统渔船避风锚地进行改扩建,以满足当地渔船锚泊避风、监控指挥、临时安置的需要.

文中利用波能聚焦的方法在实验室水池中模拟了多向聚焦极限大波,研究极限大波作用于直立圆柱引起的圆柱迎浪面波浪涌高以及圆柱正向波浪力的特点。实验模拟了不同参数的多向聚焦波浪,如谱峰频率、聚焦波幅、方向分布集中度参数和频率宽度等,实验结果表明聚焦波浪参数对圆柱迎浪面波浪涌高以及圆柱正向总力有明显的影响,圆柱迎浪面波浪涌高与波浪力的响应不同。