【作者】 汪精河；

【导师】 周晓军；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 悬浮隧道(Submerged Floating Tunnel)简称“SFT”,是一种新型的穿越水域的交通结构物。悬浮隧道有其它交通结构型式无可比拟的技术经济优势：如对结构物周围的环境影响很小,对水深和海底地形地貌、地质条件的适应性更强,减少了与陆地交通连接的引道的长度及坡度,可降低建造成本和污染等。沉管隧道、海洋平台等结构相关技术的迅速发展,使得水下悬浮隧道的建造施工已经具有了一定的基础。作为一种创新的技术,水下悬浮隧道已成为与传统交通技术相竞争的一种极其富有吸引力的技术选择。本文对定常流作用下单跨悬浮隧道管段横流向的涡激动力响应及可靠性问题进行了一些初步的理论研究,所展开的研究工作主要有：1.阐述了海流的成因、种类、统计规律,重点介绍了悬浮隧道所受海流荷载的计算方法以及涡激振动的机理和涡激升力的计算模型。2.将单跨悬浮隧道简化成两端简支Euler-Bemoulli梁,推导了具有单一的涡泄频率时,涡激升力作用下管段弯曲振动的偏微分方程,并采用分离变量法将偏微分方程化为常微分方程组,得到悬浮隧道的自振频率和各阶模态响应(位移、弯矩、剪力)的解析解。通过计算发现一阶响应起主导作用,对悬浮隧道进行动力研究时可只进行一阶动力响应分析。3.考虑了计算参数的随机性,假设升力系数Q和流速V服从正态分布,采用蒙特卡洛(Monte-Calor)法得到涡激升力幅值的概率分布为极值Ⅰ型,单位时间内(60s)跨中弯矩幅值、跨中位移幅值的概率分布为指数分布。4.讨论了结构极限状态方程的确立方法,并计算了相应的可靠度。更多还原

【Abstract】 The submerged floating tunnel (SFT) is a new traffic structure across water area. It has unparalleled technical and economic advantages compared with other types of traffic structure:such as has little effect on the environment surrounding the structures; more adaptable for water depth, seabed topography and geological conditions; reduce the length and the slope of approach linked to land transportation; reduce construction costs and polluttion, and so on. With the rapid development of technology related to immersed tube tunnels, offshore platforms and other structures, submerged floating tunnel construction has had a certain foundation. As a innovative technology, submerged floating tunnel has become a very attractive choice competing against conventional transportation technologies. This paper made some preliminary theoretical study on vortex-induced vibration and reliability of single span of submerged floating tunnel subjected to steady current in the vertical direction, the research work carried out are:1. The dissertation explained the causes, types and statistics law of ocean current, giving emphasis to coputational method of current loads on the SFT, mechanism of vortex-induced vibration and computational model of vortex lift force.2. The dissertation simplified single-span SFT as an Euler-Bernounlli beam simply supported at both ends, and derived partial differential equations of bending vibration when SFT is subjected to vortex lift force with a single vortex shedding frequency. Then transformed partial differential equations to ordinary differential equations by using separating variables method, and get the natural frequency of SFT and analytical solution of dynamic response (displacement, bending moment, shear force) under each mode. With calculating, the dissertation found first-order response play a leading role, and the dynamic study of SFT can only carried out when the first-order dynamic response.3. Considering the randomness of computational parameters, the dissertation assumed a normal distribution of lift force coefficient and velocity, then get Gumbel probability distribution of amplitude of vortex-induced lift force and exponential probability distribution of amplitude of mid-span moment and mid-span displacement in unit times (60s) by using Monte-Calor method.4. The dissertation discussed the establishment method of structural limit state expression, and calculated the corresponding reliability.更多还原