风浪流载荷下单点系泊深水养殖网箱动力学分析与性能评估

Comparing with the traditional multiple-points-mooring (MPM) cage aquaculture, the single-point-mooring (SPM) deep-water cage aquaculture is a kind of environment-friendly and economical culture pattern, which greatly reduce the environmental impacts of perennial local farming on a large scale and save the cost of mooring system more than 2/3, as well as make the construction of mooring system of SPM cages easily and simply in the open sea. However, the SPM cages exposed strong wind-wave-current are likely to face with the high risk of cage system failure destruction. when cages unable to withstand the sea overloading, the phenomenon such as anchor moving, anchor rope fracture, frame plastic failure and so on maybe take place so that causing significant economic loss to aquaculture companies. In China, all of theoretic study related with structural design, mooring style, anchor selection for SPM cages are insufficient. Therefore, the hydrodynamic performance and risk assessment for SPM cages need to be further studied. .On the basis of years of hydrodynamics studies of deep-water net cages, this study will use mathematical modeling method combined with sea in-situ test to carry out the hydrodynamic behaviors of SPM cage exposed to wind-wave-current. The main contents include revealing the dynamic characteristic and structure failure mechanism, evaluation the ultimate bearing capacity and safety life, and getting the design parameters of structural safety for the SPM cages. The above studies are aimed to provide theoretic reference and data supporting so as to enhance the safety and reliability of SPM deep-water cage aquaculture in severe marine environment.

单点系泊深水网箱养殖是一种环境友好节约型养殖模式，相比传统多点固定式网箱养殖，大大减轻了常年大规模养殖对局部海洋生态环境的影响，而且能够节约网箱海上系泊成本2/3以上，海上系泊施工简单方便。但单点系泊网箱在台风浪、强流的海洋环境下面临着系统失效破坏的较大风险，有可能因网箱系统无法承受风浪流过大载荷导致网箱走锚、锚绳断裂或框架塑性破坏的发生，在网箱结构设计、锚泊形式、固定锚的选取等方面理论支撑依据不足，相关力学性能和风险评估有待深入研究。.本项目采用数学模拟方法，结合网箱海上实测试验，开展单点系泊深水网箱在海洋风浪流环境下的动力特性，阐明单点系泊网箱动力学特性规律和结构破坏机理，评估网箱系统极限承载力与安全寿命，获取对应等级海况网箱结构安全参数。通过以上研究，应用上为单点系泊深水网箱工程设计提供理论依据和数据支撑，提升恶劣海洋环境下单点系泊网箱养殖的安全可靠性。

发展深水网箱养殖已成为我国沿海省份转变渔业经济发展方式、大幅拓展海洋养殖空间的重要举措。相比传统多点固定式网箱养殖，单点系泊深水网箱养殖是大大减轻了常年大规模养殖对局部海洋生态环境的影响，能够节约网箱海上系泊成本2/3以上。但是，单点系泊网箱有可能因网箱系统无法承受风浪流过大载荷导致网箱走锚、锚绳断裂或浮架塑性破坏的发生。为优化单点系泊网箱工程设计，保障海洋灾害环境下网箱养殖安全，系统研究海洋风浪流环境下的网箱受力、运动变形及安全性能显得尤为重要。本项目以单点系泊“六三型”深水网箱为研究对象，系统建立了可用于模拟风浪流作用下网箱系统动力响应的有限元计算模型，模拟研究了单点系泊“六三型”网箱在不同波况、流速、风速及系泊方式条件下的动力响应情况，提出了一种简单有效增强网箱浮架安全性能的技术措施，仿真分析了网箱浮架的失效及疲劳情况。针对一种单点系泊半潜式桁架结构渔场平台开展了波浪流水池试验，比较分析了不同系泊型式单点渔场平台的动力特性，确定了具有较好大浪强流抵御能力的单点系泊方式。项目取得的研究成果将对我国单点系泊深水网箱工程设计与应用具有重要的理论参考价值。