【作者】 王广地；

【导师】 高波；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2008， 博士

【摘要】 水中悬浮管段隧道一般由浮在水中一定深度的管状结构、锚固在水下基础的锚缆、杆及与两岸相连的构筑物组成。这种管段隧道代表着一种跨越水域的新型结构,与传统隧道的区别是隧道结构被水包围着,既不是位于地层中也不是穿过地层。结构通过重力、浮力以及支撑系统之间的平衡悬浮在水下一定深度,且利用支撑系统维持悬浮隧道的稳定性。由于其在环保、社会、经济效益、建造费用等方面的诸多优点,悬浮隧道正成为隧道专业方向新的研究课题,对于解决我国岛屿与大陆连接、海湾通道和近岸工程建设等无疑具有潜在的应用价值。悬浮隧道结构一般比较长,在几何特征上表现出明显的非线性。结构在自身重力、所受浮力和波、流荷载及支持系统共同作用下,可能呈现出较大的刚体位移及旋转,这无疑对悬浮隧道结构的安全性、稳定性将产生较大的影响。尽管在全球范围内还没有进入实际建设,国外许多国家对其己进行了近30年的研究,我国对悬浮隧道也进行了一些卓有成效的研究工作,但对悬浮隧道结构整体、系统性的研究仍是一片空白。本文针对以上问题主要进行了三个方面的研究工作,研究内容涉及悬浮隧道结构水动力特性分析、波流作用下悬浮隧道结构静、动力响应分析、悬浮隧道结构节段模型试验分析,论文各部分具体分析内容如下:(1)采用RNG K-ε湍流模型,利用ADINA有限元软件CFD模块对悬浮隧道大断面结构物在超高雷诺数下的绕流场进行了数值模拟,得到了悬浮隧道各基本类型断面的稳态压力系数、稳态阻力系数、脉动阻力系数以及脉动升力系数、斯特哈尔数,分析了水动力参数随断面几何构形、高宽比的变化规律。通过对各型断面水动力参数的综合比较分析,给出了悬浮隧道断面设计的指导建议,同时也为后续悬浮隧道静、动力计算分析提供必要参数取值依据,避免了参数取值的盲目性。(2)给出了利用Morison方程计算悬浮隧道结构波浪力、海流横向升力的简化计算方法,分析了悬浮隧道结构所受波流荷载随悬浮深度、海水深度、海流速度以及管段截面尺寸等参数的变化规律。(3)考虑了悬浮隧道结构与流体之间的耦合作用,采用非线性的波浪力和横向升力计算方法,建立了流体-结构耦合的悬浮隧道非线性动力分析模型。通过对动力方程进行合理的离散,利用ANSYS软件进行二次开发实现了求解过程。通过波浪作用下单跨梁悬浮隧道结构动力计算分析验证了非线性模型与线性模型计算差异,明确了悬浮隧道结构动力计算采用非线性模型的必要性。采用非线性动力分析模型,分析了悬浮隧道长度、管段截面尺寸、结构附加恒载、悬浮深度、海流速度对悬浮隧道结构动力响应的影响,在考虑结构安全性、稳定性以及经济效益的基础上提出了悬浮隧道结构设计的一些基本原则。(4)为衡量锚链振动对悬浮隧道结构的影响,对锚链在海流横向升力作用下动力响应进行了数值计算,分析了锚链预张力、海流速度、锚链长度、锚链截面积等参数对锚链横向位移、锚链轴力的影响。(5)针对悬浮隧道结构特征,将悬浮隧道管段简化为空间梁单元,锚链支持系统采用单向受拉杆单元,并考虑了锚链径向、环向运动的应力刚化效应。对悬浮隧道整体结构采用鱼骨梁模型进行建模,采用非线性动力模型进行了计算求解,分析了波流作用下锚链纵、横向布置方式、锚链长度、锚链角度、锚链距离、锚链张力对悬浮隧道结构静、动力响应的影响,给出了悬浮隧道结构锚链支持系统适用范围,设计过程中锚链支持系统设计参数的选择原则;分析了波流作用下曲线型、倒拱型悬浮隧道管体曲率对悬浮隧道结构静、动力特性的影响,给出了管体线型设计原则;通过自定义单元构造了悬浮隧道结构管段接头、驳岸接头单元,分析了接头弯曲刚度以及布置对结构静、动力特性的影响,结合结构稳定、安全性以及经济效益考虑给出了工程设计中实现的可行性。(6)悬浮隧道结构在水流力、波浪力等荷载的作用下会表现出弯曲、扭转、畸变、翘曲等变形,其力学特性十分复杂,难以通过悬浮隧道鱼刺梁模型进行分析。本文根据悬浮隧道工作环境,设计了悬浮隧道结构洋流模拟试验台,对悬浮隧道结构节段模型进行了试验研究,分析了海流作用下悬浮隧道管段空间应力状态以及锚索轴力的分布规律。更多还原

【Abstract】 Submerged floating tunnel is a new symbolization of crossing tunnel conception. Submerged floating tunnel generally consists of tube structures floating in given depth below free surface, cables linked with the anchoring foundation and structures connecting the bank sides. This type of tunnel is not constructed in the middle of stratum or through stratum. It is surrounded with water, which make it different from the traditional tunnels. The submerged floating tunnel is balanced with the self-gravity and buoyant forces and support system in the given depth. Considering many merits in environment protection, social benefits, economic benefits, construction costs and etc, submerged floating tunnel is becoming a new research subject in the tunnel profession. There are potential application values in the construction of connecting structures between the islands and the mainland, the bay crossing channesl and the offshore buildings.Considering long extension of the submerged floating tunnel in the axial direction, geometric nonlinearity is expressed obviously. In the condition of large displacement, the interaction between structures and fluid can not be avoided and wave and current force is also changed nonlinearly. In the action of gravity, buoyant force, wave and current force and support system, large rigid displacement and rotation may be produced. The reliability and stability of submerged floating tunnel structures is influenced seriously. Though the submerged floating tunnel has not been applied in the practical construction, the irrelevant research has been carried on for thirty years in many countries and the scientific efforts was afforded in domestic. Little advance was achieved in integral and system research on the submerged floating tunnels.Given the characteristics of the submerged floating tunnels, the analysis in this article was majored in three parts. It was detailed in the flow around submerged floating tubes, static and dynamic response of submerged floating tunnels subjected wave and current forces, sectional model experiment research. The detailed contents in each part were described as following:(1) Flow field around the submerged floating tunnel with large scale cross section in super high Reynolds number was simulated using RNG K-εturbulent model with CFD module of ADINA program. The pressure coefficient and drag coefficient of different section type in steady state were obtained as well as drag coefficient and lift coefficient in impulsive motion and Strouhal number. The variation of the hydrodynamic parameters with different geometric configuration and aspect ratio was analyzed. With the general comparison of the hydrodynamic parameters, each type of cross section was evaluated and guidelines for the section design were presented. The parameters required in the static and dynamic analysis of the submerged floating tunnels were offered. Thus, inaccuracy of parameters can be avoided.(2) Simplified method for calculating the wave and current force with Morison formula was introduced. The parameters influencing on the wave and current force were analyzed such as depth of structures, depth of sea, current velocity and scale of cross section.(3) In the conditiion of large displacement, the interaction between the structures and fluid can not be ignored. The wave and current forces change nonlinearly. Nonlinear dynamic analysis model considering the interaction of submerged floating tunnel structures and fluid was constructed with nonlinear calculation method of the wave force and the lateral lift force. Based on the appropriate discrete approximation, the solution procedure was implemented with the secondary development of the ANSYS program. The difference of the response in the nonlinear model and the linear model was verified with the numerical dynamic analysis of single span submerged floating tunnel structures. It is proved that the nonlinear model is the mandatory requirement in the dynamic analysis of the submerged floating tunnel. The parameters influencing on the response of submerged floating tunnel were analyzed with nonlinear model such as the length of structures, the scale of cross section, the additional permanent load, the depth of structures, the current velocity. Considering the reliability and stability and economic benefits of the structures, the primary principles for the submerged floating tunnel structures were put forward.(4) In order to evaluate the influencing of cable on the submerged floating tunnel structures, the dynamic response of the cable subjected current force was numerical simulated. The parameters influencing on the lateral displacement and axial force of the cable were analyzed such as the pre-tensile force, the current velocity, the cable length, the scale of cable cross section.(5) Considering the characteristics of the submerged floating tunnels, the tubes were simplified into the spatial beam element. The cables were simulated with link element and the longitudinal and perpendicular stiffness was considered. The submerged floating tunnel was constructed with the herringbone beam model and the solution was obtained with nonlinear dynamic method. The parameters influencing on the static and dynamic response of submerge floating tunnel structures with the circular section and the straight line body were analyzed such as the longitudinal and transverse layout of cable, the cable length, the layout angle of cable, the layout distance of cable, the pre-tensile of cable. Taking the submerge floating tunnel with the circular section and the lopsided layout of the cables as example, the parameters influencing on the static and dynamic response of the structures were analyzed such as the curvature of the curved and the invert submerged floating tunnel. The tube junction and the waterfront junction element was created with the modification of the user defined element. The bending rigidity and the distribution of junctions influencing on static and dynamic response of the submerge floating tunnel were analyzed. In the view of stability and the security of structures and the economic benefits, the feasibility of application in the construction was analyzed.(6) The spatial mechanical characteristics of the submerged floating tunnel structures were extraordinary. The special phenomenons can be produced such as bending, twisting, distortion and warping. It can not be analyzed with herringbone beam model. According the work circumstance of the submerged floating tunnel, the submerged floating tunnel test platform was constructed. The segmental model experiments of submerged floating tunnel were carried on. The spatial stress distribution of the segmental model and the axial force of cable were analyzed.更多还原