【作者】 孙胜男；

【导师】 陈健云；

【作者基本信息】 大连理工大学 ， 防灾减灾工程及防护工程， 2008， 博士

【摘要】 悬浮隧道概念的问世时间虽然短暂,然而由于它在跨越深水域时的明显优势,悬浮隧道现已得到世人的广泛关注。悬浮隧道一般由悬浮在水中的管体组成,由浮力保持在适当的位置上,通过合理的锚固系统如锚索或张力腿锚固在海床上。因此,相对传统隧道而言,悬浮隧道在环境荷载作用下更容易产生振动。悬浮隧道的振动可以分为整体振动和局部振动。整体振动是指只考虑管体的振动,不考虑锚索的横向振动;局部振动是指单根锚索的振动。本文从悬浮隧道的整体振动和锚索的局部振动两个方面出发,考虑到中国地震的多发性和锚索振动的关键性,对地震作用下悬浮隧道体系的整体动力响应以及参数激励与强迫激励作用下锚索的振动特性进行了研究分析,并对锚索的被动控制进行了初探。主要内容如下:(1)介绍了悬浮隧道的概念、特点、发展历程及结构分析进展。无论怎样的现场条件、施工方法和设计方案,必须解决结构建模和分析方法问题。因此,本文从隧道管体结构、隧道锚固体系、作用荷载、模型试验等方面综述了国内外对悬浮隧道结构分析方面的研究进展,提出了其发展方向和应专门研究的关键技术问题,以供我国进一步开展有关研究和制定相关标准和规范时参考。(2)悬浮隧道尚未有实际结构物,模型试验不失为研究其受力特性和动力响应的重要手段。为模拟悬浮隧道-水体相互作用的真实情况,利用大连理工大学海岸和近海工程国家重点实验室的大型水下振动台,首次进行了悬浮隧道地震响应的模型试验。根据模型试验的试验现象和数据,分析了悬浮隧道地震时的反应特点,以及悬浮隧道动力反应的影响因素。(3)在势流理论的基础上,对悬浮隧道进行了地震响应数值分析。为确保数值模型的正确性,首先建立了贴近悬浮隧道地震响应模型试验的数值模型,将计算结果与试验结果进行了对比;然后在验证数值模型正确的基础上,参考国内外拟建悬浮隧道的设计参数,建立了悬浮隧道的数值模型,对悬浮隧道进行了模态分析和地震响应影响因素敏感性分析。(4)为研究参数激励作用下锚索的动力响应,提出了悬浮隧道锚索-管体耦合非线性参数振动模型,建立了锚索-管体的耦合振动方程,通过伽辽金法和龙格-库塔法分析了悬浮隧道锚索在参数激励作用下出现大幅振动的可能性。鉴于锚索垂度效应的重要性,分别采用两种不同的方式来考虑垂度—求解方便、规律性强的等效弹性模量法和体现锚索垂度效应的抛物线法。(5)将悬浮隧道锚索简化为受张力的简支梁,建立了锚索的涡激振动方程,研究了流场中锚索的多阶横向涡激振动问题,数值分析表明了锚索高阶涡激非线性振动的重要性。此外,建立了悬浮隧道锚索-管体耦合振动非线性模型,对参数激励进行了比较真实的模拟,考虑了隧道管体的运动对锚索横向振动的影响,并在此条件下探讨了流场中锚索的涡激振动问题。(6)以锚索和粘弹性阻尼器组成的系统为研究对象,考虑锚索的垂度效应,建立了锚索-粘弹性阻尼器的振动方程,通过伽辽金法得到了系统的振动常微分方程组,然后进行复特征值分析,得到了锚索可能达到的最优阻尼比以及相应的最优阻尼器系数,分析了锚索的倾角和垂度对锚索最优阻尼比的影响。更多还原

【Abstract】 Though submerged floating tunnel (SFT) is an innovative concept, it has gained more and more attention worldwide for its advantages in the crossing of deep water. SFT basically consists of a tunnel floating in the water, due to positive net buoyancy, at some convenient depth and fixed to the seabed by means of a suitable anchoring system, encompassing tethers or tension legs. Thus, it can be seen that the SFT is much more prone to undergo significant oscillations due to dynamic effects than traditional tunnels.Vibration of submerged floating tunnel may be expressed as combination of global and local modes. Global mode is defined as the vibration of the tube in which the tethers are treated as elastic tendons with no independent transverse motion, while the local mode is that of a tether fixed at the two ends. In this paper, we dealt with dynamic response of submerged floating tunnel from two aspects: global mode and local mode. Taking the frequent earthquake in China and importance of tether vibration into account, the global dynamic response of submerged floating tunnel under the earthquake and the tether vibration under parametric excitation and forced excitation were performed. Moreover, a preliminary study on the passive control of tether vibration was presented. The main contributions are summarized as follows:(1) This paper introduced the concept, features, development of submerged floating tunnel and stated the state-of-art of its structural analysis from several aspects such as tube, anchor system, load and model experiment. Also, the development direction and key problems that need to be solved were presented. All of these are benificial to further research and new standards.(2) Until now, no submerged floating tunnel has been built yet. Thus, model experiments are very important to dynamic response of submerged floating tunnel. To simulate the real situation of coupled submerged floating tunnel-water, the first model experiment of submerged floating tunnel under the earthquake at home and abroad was performed on the large-scale underwater shaking table in Dalian University of Technology. According to the experimental phenomena and data, the seismic characteristics and main effect factors for dynamic response of submerged floating tunnel were analyzed.(3) Based on the potential fluid theory, seismic response of submerged floating tunnel was studied by numerical analysis. To ensure the validity of numerical model, firstly, numerical model close to the seismic response model experiment was set up. The results were compared with those of model experiment. It can be seen that the numerical results are basically identical with those of shaking table test. Numerical model adopted is effective for dynamic response of SFT. Secondly, according to the parameters of designed SFT at home and abroad, modal analysis and main effect factors for dynamic response of submerged floating tunnel were analyzed by numerical method.(4) To analyze dynamic response of tether under parametric excitation, a theoretical model of coupled tether-tube was developed. Also, the corresponding vibration equation is set up. By Galerkin method and Runge-Kutta method, the possibility of large-amplitude vibration of submerged floating tunnel tether under parametric excitation was on discussion. Since the tether sag effect is very importance, sag in this paper was considered by two methods—convenient equivalent elastic modulus method and parabola method that may reflect the sag effect.(5) Taking the tether of submerged floating tunnel as a beam with strain, the equation of vortex-induced vibration of tether was set up. Multi-order vortex-induced nonlinear vibration of submerged floating tunnel tether subjected to current was discussed. The importance of its high-order vortex-induced nonlinear vibration was illustrated in numerical examples. In addition, to simulate the parametric excitation accurately, a nonlinear tether-tube model of submerged floating tunnel was proposed. Under this condition, the transversal oscillation response of tether under vortex-induced vibration and parametric vibration was analyzed.(6) Taking the system that consists of tether and visco-elastic dampers as research object, the vibration equation of tether and visco-elastic damper was set up considering tether sag effect. By means of Galerkin method, the partial differential equation was transformed into a set of ordinary ones. Subsequently, maximum damping ratios and corresponding optimal damper coefficients were obtained by complex eigenvalue analysis.更多还原