【作者】 左生荣；

【导师】 杨吉新；

【作者基本信息】 武汉理工大学 ， 道路与铁道工程， 2013， 博士

【摘要】 跨海大桥中水下墩柱结构由于所处环境的复杂性,虽然刚度比较大,但是在波浪、波流、地震以及飓风等海上动力荷载作用下容易产生较大的动力响应,长期频繁的作用会导致结构引起疲劳损伤甚至破坏。因此,对水下墩柱结构受到波浪和水流等海洋环境荷载作用下的研究就显得十分重要,对水下墩柱结构的设计乃至建成后的安全运营都有着重要的现实意义。本文从跨海大桥桥墩所处环境的特殊性出发,首先基于波浪理论和波浪力的计算方法,对不同尺寸和形状的墩柱的波浪力计算方法进行了比较,然后运用验证过的CDF数值计算的方法对不同形式的墩柱以及不同参数的波浪分别进行了数值计算,并进行了规律性的总结,最后分别模拟了均匀流和波流联合对圆形墩柱的作用并对墩柱的响应进行了分析,主要研究内容如下：1.论文在分析了该课题的研究背景和现实意义的基础上,对国内外波浪和波流对结构作用的相关理论以及在波浪和波流共同作用下对水中墩式结构动力响应的相关研究进行了归纳和总结,并针对不同尺寸和不同形状的墩柱所采用的波浪力计算方法进行了比较。2.提出了基于CFD的墩柱波浪力数值计算方法,为验证CFD计算方法的准确性,分别把CFD对于小直径墩柱的计算结果与莫里森公式的解析解进行了对比。在实验条件缺乏的前提下,利用现有文献中的实验测得的数据跟CFD数值计算的结果进行对比,以此来验证数值求解方法的准确性。3.用CFD数值计算法对作用于不同形状的大尺寸墩柱上的波浪力进行了计算分析,首先在模型网格划分时,以4m圆形墩柱模型为例,通过加密计算域的网格进行波浪力的计算,根据计算结果来验证网格的变化对于计算结果精度的影响,通过观察数值计算后的波浪力时程图,得到了墩柱上波浪力跟波浪周期之间的变化规律；然后,通过改变模型的形状,以4m×4m的方形墩柱来进行波浪力的计算并与圆形墩柱进行对比得出波浪力的变化规律；接下来,通过改变波长和波高两个波浪参数分别来分析两个参数变化后波浪力的变化规律并得到其对波浪力大小的影响程度；再次,为了研究波浪力在墩柱垂直方向的分布规律,分别求出墩柱上不同位置上的波浪力绘成变化图,并分析得到波浪力在墩柱垂直方向上的分布规律；最后,通过计算出来的波浪力来进行不同墩柱上的结构动力响应分析。4.分析了均匀水流作用下的圆形墩柱绕流及涡激振动,研究了波浪与大尺度圆形墩柱作用产生的绕射、反射现象；基于标准k-ε湍流模型,分别对大圆形墩柱采用二维数值模拟和三维数值模拟的方法,对在一定流速下圆形墩柱中间深度平面上的绕流流场的压力分布和速度分布进行了分析；对水流作用下圆形墩柱尾流区涡旋发展的一个周期的过程进行了描述,探讨了均匀水流作用下水中墩柱结构动力响应规律；最后通过数值计算得出了均匀水流对圆形墩柱作用力值以及在墩柱上的分布规律。5.对圆形墩柱在波浪和均匀水流的联合作用下的流场变化特点进行了研究,首先探讨了波流联合作用的方法和机理；然后对波流联合作用下圆形墩柱不同深度上的绕流流场的压力分布和速度分布进行比较分析；最后通过数值计算得到了波流联合作用的最大波流力,并与波浪和水流分别作用的最大波浪力叠加值大小进行比较、分析了原因,同时也求得了大直径圆形墩柱的最大变形和应力值。最后,在对全文研究工作的基础上作了深入的总结并提出了本文的创新点,也对需要进一步深入开展的工作进行了说明。更多还原

【Abstract】 Since the environment of underwater bridge pier structure is complicated, although the rigidity is relatively large, but in the waves, wave and current, earthquakes and hurricanes and other marine dynamic loads prone to large dynamic response, underwater bridge pier can cause structural damage or even fatigue damage in long-term effect of frequent loads, therefore, it is very important to carry out the research of the underwater pier structural by waves and currents and other marine environments loads designing of the underwater piers,even in the operation stage,the security operations,it also has practical significance.In this paper, from the bay bridge pier according to the characteristics of the particularity of environment.Firstly, based on the wave theory and wave force calculation method, the different sizes and shapes of piers wave force calculation methods were compared,then the use of validated the CDF numerical methods as well as different forms of pier waves of different parameters were calculated numerically, and conducted regular.Finally, the paper simulated the role of circular piers combined action of waves and uniform flow and analyzed the response of the piers.The main contents of the thesis are as follows:1.Thesis analyzes the research background and practical significance, based on the domestic role of waves and uniform flow related theories of the structure as well as in joint action of waves and uniform flow pier structure on the dynamic response of water related research carried out and summarized, and compared wave force with different size and shape of the piers in the second chapter.2.It proposed a pier wave force method based on CFD numerical and the analytical calculation results by using the method of numerical solutions are compared with Morison formula, and compared with experimental data in existing literature to the numerical results, in order to verify the reliability of numerical solution method.3. Using CFD software calculation method of wave force acting on a different shape and size of pier is calculated, the mesh model, a dimensional cylindrical model as an example, the computational domain grid wave force through encryption calculation, according to the calculated results to verify the grid change to affect the accuracy of the calculation results of; through numerical simulation, we can see changes of wave forces on piers and the relationship with the wave period between; and by the different shapes and different sizes model calculated results are compared and analyzed,the change law between them; the change law of two wave parameters to analysis the parameters of wave force and wave height and wave length are changes affect the range of depth of pier degree;by calculating the wave forces on different positions of the pier column, summarize the distribution of wave forces on piers on; for maximum wave force acting on the structure dynamic pier column of different models are compared and analyzed on the response.4.Even under the action of water flow on the flow around a circular cylinder and the vortex induced vibration phenomena are briefly introduced; based on standard turbulence model, are used for numerical simulation of2D and3D simulations of large cylinder, a flow in cylindrical certain depth on the flow field around the pressure distribution and velocity distribution was analyzed; the process of water under the action of cylinder wake vortex development in a cycle is described, discussed the uniform flow of water dynamic response of the pier column structure.5. In the joint action of wave and uniform flow under the comprehensive effect on the cylinder were studied, first introduced the principle and method of combined wave current action; and then flow combined effects of wave flow around a circular cylinder with flow effects were compared, in a flow rate of a depth of cylinder on the flow field around the pressure distribution and velocity distribution were compared and analyzed; finally obtained by numerical calculation combined wave current maximum wave force and wave and current respectively maximum wave force superposition value are compared, and reasons are analyzed, and dynamic response of large diameter cylinder of the obtained results.Finally, this paper summarizes the research work and raised the need for further research and the problems to be solved.更多还原