【作者】 刘洪杰；

【导师】 李玉成；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2003， 博士

【摘要】 近年来许多国家都在新建深水码头和防波堤，传统的直立式结构已经不能满足工程实际需要。为了减少波浪的反射和结构所受的波浪力以降低工程造价，近几十年来各国竞相研究各种新型防波堤结构。其中开孔沉箱受到了人们越来越多的重视，它能够减小波浪的反射和开孔结构物的所受的波浪力。 本文从理论分析和试验研究两个方面对斜向波与开孔沉箱的相互作用进行了深入研究。通过斜向波与带有横向隔板沉箱和局部开孔沉箱结构的相互作用的理论分析，得到了开孔结构对波浪的反射率和所受波浪力，通过试验结果与理论计算结果的对比，验证了上述理论的正确和有效性。详细讨论了工程常用范围内的各种影响参数对反射率和沉箱所受总水平力比的影响。 给出了带有横隔板的双层全开孔沉箱结构和双层局部开孔沉箱结构与斜向波相互作用的理论求解方法。数值计算结果表明，在工程常见的范围内，双层开孔板沉箱能够降低波浪对结构的作用力，是否采用双层开孔板结构主要取决于开孔结构的几何尺寸。 在大连理工大学海岸和近海工程国家重点实验室的多功能水池内进行了开孔沉箱结构物与斜向波相互作用的三维物理模型试验。通过试验数据的分析，验证了已有的正向入射波条件下计算开孔结构物对波浪的反射率和结构自身所受总水平波浪力比的经验公式。考虑了多种相关因素对斜向波与开孔沉箱结构相互作用时开孔结构对波浪的反射率和结构所受波浪力的影响，首次提出以k_r^θ/k_r⁰（k_r^θ是入射角度为θ条件下开孔沉箱结构对波浪的反射率，k_r⁰是波浪正向入射条件下，开孔沉箱结构对波浪的反射率）作为研究斜向波与开孔沉箱相互作用的反射率的无因次参数，用最小二乘法得到了计算k_r^θ／k_r⁰的简化公式，计算结果与试验数据符合较好；本文基于线性波理论，首次证明在工程常用条件下，单位长度上开孔沉箱结构所受的总水平波峰波浪力与波浪入射角不相关；由理论计算成果得到了简化公式，可用于计算斜向规则波作用于不同长度开孔沉箱上的平均波峰力与该入射角单宽波峰力的比值F₁^θ／F₁^θ。更多还原

【Abstract】 In the recent years, in order to reduce the total costs on project by diminishing the wave reflection and the wave force, many countries have conducted researches to study new type of caissons. The main emphases are focused on the perforated caissons because of two reasons: Firstly, the wave force acting on the front wall of a solid structure can be divided into two parts on two different walls with phase difference. The phase difference between the forces on the two walls is related to the distance between the two plates. To select the distance between the two plates suitably, the total wave force on the whole structure could be maintained at a lower level. Secondly, waves will dissipate when they transmit over a porous medium. Consequently, the reflection rate of waves from breakwaters can be reduced, and the wave run-up in front of the structure could be reduced, too.Based on three-dimensional experiment and the potential theory as well as eigen function expansion method, the interaction between oblique incident wave and caisson breakwater with traverse wall and the interaction of the oblique incident wave with partially-perforated caisson breakwater have been investigated. The experimental data have been compared with the theoretical results and a good result can be found. The effects of many parameters on wave reflection and wave force are discussed in details in the range of engineering practice.Theoretical solutions have been found to study the effect of double-layered perforated caisson on wave force and wave reflection based on the aforementioned two types of structures. Results obtained from numerical calculation show that in the range of engineering practice the wave force acting on double-layered perforated caisson breakwaters is less than that of single-layered perforated caisson breakwaters. Whether or not to adopt the double-layered caisson breakwater lies on the geometrical dimension of the caisson.Three-dimensional experiments have been undertaken in multi-function basin of the State Key Laboratory o f Coastal and Offshore Engineering, Dalian University of Technology. The sound consistency can be found between experimental data and the existing empirical equations. A new dimensionless parameter kθr Ik皉 (where kθr is the reflection coefficient by structures when incident angles is 9 ; kr?is the reflection coefficient by structures when incident angle is 0?) has been proposed to study the reflection coefficient of oblique incident wave with perforated caisson breakwater. By using the Ordinary Least Square Estimation, an empirical formula has been made to calculate kθr I k皉. The results of empirical and the experimental data show the sound consistency with each other. Based on linear wave theory, the paper illustrates that in the range of engineering practice, the wave force on unit length of perforated caissons has less impacts with incident angles. On the basis of the theoreticalresults, a new equation has been educed to calculate F,e I F1(ratio of the wave force on different length of structures to that on unit length of structures).更多还原