【作者】 董华洋；

【导师】 王永学；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2009， 博士

【摘要】 港口建设已逐步进入到深水浪大、环境条件恶劣的海域。传统的坐底式防波堤结构已不能满足深水港口建设的要求。为此,研究消波效果好、造价低廉、适应软土地基,满足港内水质环境要求的防波堤结构型式,具有重要的意义。基于此,本文提出了垂直导桩锚泊浮箱-水平板式浮防波堤和锚链锚泊浮箱-水平板式浮防波堤两种结构型式,并对这两种新型浮式防波堤的水动力特性进行了物理模型试验和数值模型计算研究。另外对浮箱式浮防波堤的水动力特性也开展了物理模型试验和数值模型计算研究工作。首先,对浮箱式浮防波堤开展了物理模型试验,研究了规则波作用下浮箱式浮防波堤的透射系数、运动响应和锚链受力特性。探讨了相对宽度、波高、锚链相对拖地系数、锚链刚度、导链孔处倾角以及浮箱相对吃水对浮箱式浮防波堤水动力特性的影响。另外对浮箱式浮防波堤的透射系数与锚链受力的相关性进行了研究。试验结果表明,改变相对宽度、锚链刚度和导链孔处倾角对透射系数、运动响应和锚链受力影响均较大。其次,对垂直导桩锚泊浮箱-水平板式浮防波堤开展了物理模型试验和数值模型计算研究。通过物理模型试验研究了规则波作用下垂直导桩锚泊浮箱-水平板式浮防波堤的透射系数和垂荡运动响应。探讨了相对宽度、波高、水平板宽、水平板层数,水平板与浮箱间距以及浮箱相对吃水对消波系数(包括透射系数、反射系数、波能衰减系数)和垂荡运动响应的影响。并对消波系数与垂荡运动的相关性进行了分析。试验结果表明,垂直导桩锚泊浮箱-水平板式浮防波堤在相对宽度为0.2时,可使透射系数低于0.5;即使在长周期波浪(在试验范围内,周期为1.28s～1.55s的波浪)作用时,透射系数也可降至0.8左右。根据本文的试验成果,浮箱下部设置一层板型式的垂直导桩锚泊浮箱-水平板式浮防波堤的消波效果较为理想。基于线性时域理论,建立波浪对浮箱-水平板式浮防波堤作用的时域内的积分方程,应用边界元方法求解,再应用牛顿第二定律建立浮箱-水平板式浮防波堤的时域运动方程,采用四阶Runge-Kutta方法求解,由此建立起浮箱-水平板式浮防波堤的数值模型。根据该数值模型对垂直导桩锚泊浮箱-水平板式浮防波堤的消波系数和垂荡运动响应进行了计算并与试验结果进行对比。另外应用数值模型计算了垂直导桩锚泊浮箱-水平板式浮防波堤的导桩所受水平力。最后,对锚链锚泊浮箱-水平板式浮防波堤开展了物理模型试验研究和数值模型计算研究。通过物理模型试验探讨了规则波作用下,水平板层数不同、浮箱吃水不同对透射系数的影响。锚链锚泊浮箱-水平板式浮防波堤的浮体部分的数值模型的建立方法与垂直导桩锚泊浮箱-水平板式浮防波堤相同,锚链采用静态悬链线方法模拟。应用数值模型计算了水平板不同的锚链锚泊浮箱-水平板式浮防波堤的透射系数、运动响应和迎浪面、背浪面锚链受力特性。试验结果和计算结果均表明:锚链锚泊浮箱-水平板式浮防波堤的运动响应和锚链受力均小于锚链锚泊浮箱式浮防波堤。锚链锚泊浮箱-水平板式浮防波堤较锚链锚泊浮箱式浮防波堤具有更好的消波效果。更多还原

【Abstract】 The construction of harbors steps into deep sea water area with execrable circumstances. The conventional breakwaters can not be fit for the construction in deep water. Therefore, it is very significant to explore the breakwaters with good performance of dissipating waves, which can be fit for poor foundation, high demanding of water circulation and cheap cost.For these reasons, the two new types of floating breakwater, the pile-restrained pontoon-plates floating breakwater and mooring chain restrained pontoon-plates floating breakwater, are proposed in this dissertation. Based on the model test, and by numerical investigation, the hydrodynamic prosperities of the two new types of floating breakwater are investigated. Additionally, the hydrodynamic prosperities of mooring chain restrained floating breakwater is studied by the physical model test and numerical investigation.Firstly, the transmission coefficients, motion responses and mooring chain forces of the floating breakwater under regular wave action are researched by experiments. The influences of relative pontoon width, wave height, relative drag coefficient of mooring chain, mooring chain stiffness, angle at anchor point and relative pontoon draught on the hydrodynamics characteristics are investigated. The correlativity between transmission coefficients and mooring chain forces are studied. The experimental results demonstrate that relative width, mooring chain stiffness and angle at anchor point have large effect on transmission coefficients, motion responses and mooring chain forces.Secondly, the experimental study and numerical model investigation are conducted on the pile-restrained pontoon-plates floating breakwater under regular wave actions in the finite water depth. The emphasis of the experimental investigation is on the characteristics of disspating coefficients and motion responses of the pile-restrained pontoon-plates floating breakwater. The influences of relative width, wave height, width of plates, distance between pontoon and plate, relative draught of pontoon on the dissipating coefficients and heave motions are discussed. The correlation between dissipating wave coefficients and heave motions are analyzed. The experimental results indicate that the transmission coefficient is less than 0.5 when the relative width is 0.2. Even under the long period wave (the wave period is from 1.28s to 1.55s) action, the transmission coefficient of the pile-restrained pontoon-plates floating breakwater decrease to 0.8. According to the experimental results, it is proposed that the pile-restrained pontoon and one plate floating breakwater has good ability of dissipating wave. Based on linear time-domain theory, the integral function is established, and solved by the boundary element method. By Newton second’s law, the time-domain motion equations of the mooring chain restrained pontoon-plates floating breakwater are built and solved by the fourth order Runger-Kutta method. On the basis of the theories above, the time-domain numerical model is developed. Using this numerical model, the dissipating coefficients and heave motion responses are calculated. And the numerical results of dissipating coefficients and heave motion are compared with experimental results. Additionally, the horizontal forces on pile of the pile-restrained pontoon-plates floating breakwater are calculated at the same time.Thirdly, the experimental investigation and numerical model study are developed on mooring chain restrained pontoon-plates floating breakwater. The influences of the number of plate and pontoon draught on the transmission coefficients are discussed. The method of building numerical models of the floating of mooring chain restrained pontoon-plates floating breakwater is the same with that of the pile-restrained pontoon-plates floating breakwater. The The catenary theory is utilized to calculate the mooring chain forces. The model can reflect the characteristics of transmission coefficients, motion responses and mooring chain forces. Both the experimental results and numerical results show that By using the numerical model, the motion responses and mooring chain forces of mooring chain restrained pontoon-plates floating breakwater and pontoon floating breakwater are all calculated under different wave action. The results indicate that the motion responses and mooring chain forces of mooring chain restrained pontoon-plates floating breakwater are less than that of the pontoon floating breakwater, and the mooring chain restrained pontoon-plates floating breakwater has better dissipating wave ability than mooring chain restrained pontoon floating breakwater.更多还原