桩基环保型防波堤的基础理论与设计方法

The breakwater is an important kind of coastal defenses, which aims to provide protection for the population and infrastructure in coastal zones. The construction of a breakwater proposes high demand of its economy and security. Furthermore, the least negative environmental impacts also become vital standards of constructing a breakwater, due to its significant influence on erosion and deposition properties caused by the block of stream flow. The environment friendly breakwater, which can not only protect infrastructures against storm surge and large waves but also minimize the impact on hydrodynamic environment, sedimentary environment, and deterioration of ecological environment, has become a trend of development. Under complex and severe hydrodynamic conditions, the buckling failure of a structure can be induced by excessive wave-current loads and foundation scour, and on the other hand it may not satisfy the environment protection requirements because the poor permeability plays a key role in the sediment erosion and deposition. At present, the available basic theory and analysis methods can hardly be used to guide the design and construction of breakwaters. This project will focus on the design of safe and environment friendly breakwaters in the framework of wave-current interaction, and investigate:①the micro-scale hydrodynamic characteristics and hydrodynamic load analysis of environment friendly pile breakwater; ②mechanisms of wave attenuation, water permeability, wave-current forces and current momentum reductions; ③the law of local foundation scour under wave-current interaction; ④development of new techniques for analyzing the hydrodynamics and scour characteristics of environment friendly breakwaters under wave-current interaction. The research results are expected to provide theoretical basis and design standards of breakwaters for the development of coastal resources such as mining, fisheries, wetlands and tourism.

防波堤作为重要的海岸工程设施，其建设不但对安全性和经济性提出更高要求，由于实体防波堤对水流的阻挡导致的冲刷和淤积影响大，降低工程产生的负面环境影响也成为建设要求的重要指标。既能够抵御削减波浪影响，又能最大程度减轻对自然环境影响的环保型防波堤成为发展趋势。在复杂严酷动力条件下，结构会因波流 荷载和基础冲刷过大而失稳破坏，也会因透水性不够对泥沙冲淤产生显著影响而无法满足环保要求。目前已有相关基础 理论与分析手段难以很好指导此类构筑物设计和建设。本项目围绕着环保型防波堤的安全与环保设计，开展波流耦合作用下：①桩基环保型防波堤的水动力场微观特性和波流力分析；②消浪、透水性能和其对波流力与海流动量折减机理；③进行波流耦合作用下防波堤的基础冲刷规律；④发展波流耦合 作用下的环保型防波堤水动力与冲刷分析新技术。研究成果将为海岸带丰富的矿产、渔业、湿地、旅游等资源开发提供理论研究和设计方法依据。

防波堤作为重要的海岸工程设施，除考虑安全性和经济性外，由于其对水流的阻挡导致的冲刷和淤积影响大，降低负面环境影响也成为建设的重要要求。既能够抵御削减波浪，又能最大程度减轻对自然环境影响的环保型防波堤成为发展趋势。目前已有相关基础理论与分析手段难以很好指导此类构筑物设计和建设。. 本项目围绕桩基环保型防波堤的功能性、安全性与环保性，对不同桩基环保型防波堤的消浪能力、透流能力与基础冲刷稳定性及其环境影响规律开展研究，编制了国家行业标准和团体标准。具体内容如下：①充分研究结构构件力学性能、组合后的空间特征和环境特点，发明了16种不同典型环保型防波堤结构类型和8种新型防波堤多功能结构；②明确透空型防波堤关键水动力特性，阐明透空式防波堤消浪、透流机理，建立了新型数值模型，揭示了极端环境下防波堤荷载特征；③阐明了不同类型桩基局部冲刷机理，发展了平衡冲刷深度的预测方法，基于改进的延迟分离涡模型、瞬态输沙计算方法及动网格技术，构建了结构物局部泥冲刷过程精细化数值模型；④确定防波堤对海流动量的源汇项折减表达式，在典型海洋环境数值模型中修正动量方程，纳入防波堤对水动力环境的影响，阐明了防波堤对海域物质输运过程和水交换能力的影响机理。. 本项目研究成果为桩基环保型防波堤的应用提供了科学的设计参考和依据，已经支撑了多个港口工程，助力海洋资源开发实现经济-安全-环保的工程效果。