【作者】 刘文硕；

【导师】 戴公连；

【作者基本信息】 中南大学 ， 土木工程， 2013， 博士

【摘要】 摘要：高速铁路大跨度桥梁温度跨度大、活载作用下梁端转角大,且常承载多线铁路,桥梁与轨道因非线性约束的作用构成相互耦合相互制约的力学平衡体系,梁轨间相互作用是大跨度桥梁与无缝线路设计及安全使用的重要控制因素之一。本文以高速铁路线上的大跨度钢桁拱桥为研究对象,基于大跨度桥梁与轨道结构的非线性空间分析理论,建立了反映线路阻力非线性特性的梁轨一体化空间耦合模型,编制开发了计算模块,考虑了梁轨体系内加载历史的影响,对该类桥梁在温度、活载、地震激励等多场耦合作用下的梁轨相互作用特性和桥上无缝线路轨道结构的稳定性及钢轨断裂进行了研究。本文主要研究内容如下：(1)基于无缝线路纵向阻力的时变特性,推导了纵向阻力的迭代公式,改进了梁轨间纵向阻力的模拟方式,提出了实现线路阻力在无载、有载工况间自由转换的“阻力差值法”,该方法能考虑加载历史对梁轨非保守系统的影响,可对温度滞回、列车过桥、列车桥上制动等过程进行全历程分析。(2)建立了轨道-桥面板-纵横梁-主桁架-墩台-基础一体化的钢桁拱桥梁轨系统空间耦合模型,采用改进的“重叠非线性杆单元”模拟梁轨间纵向阻力,选用考虑卸载的理想弹塑性阻力模型来计入加载历史的影响,模拟了线路的纵、横向阻力及竖向刚度,该模型能更准确地反映轨道、桥面、纵横梁、主桁架、支座、桥墩、桩基等各组成间的关系,可模拟单线行车、多线行车等不同工况,可同时对梁轨间纵向附加力与桥上轨道稳定性进行分析。通过与相关文献算例进行对比,验证了本文模型的可靠性。(3)研究了钢桁拱桥梁轨间各项纵向附加力的特征及分布规律,对考虑加载历史的多荷载耦合非线性分析与线性叠加结果进行了对比性分析,探讨了温度组合工况、行车方向、活载模式、列车编组、制动力率、线路阻力、墩台刚度、临跨桥梁布置、活动支座摩擦力等敏感因素对梁轨纵向力的影响,阐述了钢轨伸缩调节器、轨道结构型式、桥墩上锁定阻尼装置及桥面系型式对无缝线路纵向力的削减机理及优选布置方案。(4)以轨道初始水平不平顺与高低不平顺的耦合为初始条件,对大跨度钢桁拱桥桥上无缝线路的轨道稳定性及钢轨断裂力传递进行了研究,对比研究了考虑梁轨相互作用与否时轨道的失稳状态,探讨了钢轨类型、道床横向阻力、线路竖向刚度及初始不平顺矢度等敏感性因素对桥上轨道结构稳定性的影响,同时对钢轨瞬态断裂过程进行了全历程追踪,对静态、动态断轨力进行了比较。(5)采用改进的Penzien模型模拟桩土效应,编制了人工地震波生成程序,分析了考虑轨道约束与否对大跨度钢桁拱桥梁轨系统自振特性的影响,总结了不同地震动输入模式下(包括地震波频谱特性、场地相位差等)大跨度钢桁拱桥梁轨系统的地震响应,探讨了道床阻力、滑动支座摩擦效应、相邻结构支座布置、墩台刚度等因素对其梁轨系统地震力的的影响规律,并对温度力、制动挠曲力与地震荷载的耦合作用进行了研究,提出设置伸缩调节器、粘滞阻尼器及比选轨道结构型式等梁轨适应性措施。更多还原

【Abstract】 Abstract:For long-span bridges on high-speed railway (HSR), the expansion length and the deck-end rotation are relatively large. Carrying multiple railway lines, the bridge and the track constitute a mechanical equilibrium system due to the nonlinear constraint between them. In general, the track-bridge interaction is a quite significant dominant factor for the design and safe operation of the long-span bridges and continuous welded rails (CWR).In this dissertation, the long-span steel-truss arch bridge in HSR was discussed and researched. Integrative coupling spatial models, considering the nonlinear characteristics of resistance between the bridge and the track, were established on the basis of nonlinear analytical theory of long-span bridge. By developing specialized calculating modules, taking the effect of loading history into account, the numerical research was focused on the mechanical characteristics of the CWR and long-span steel-truss arch bridge system subjected to the multi-field coupling actions of temperature, traffic loads and seismic load. In addition, the stability of CWR on arch bridge as well as the transient fracture process of rails were investigated. The main contents of this dissertation are given as follows:1. Based on the time-varying characteristic of longitudinal resistance between track and bridge, the iterative formulas were derived, and the simulating method has been improved. Furthermore, the Resistance-difference Method was proposed to transfer the resistance from unloaded condition to loaded condition freely, and vice versa. Adopting this new method considering the influence of previous load history on nonconservative mechanical system of track and bridge, the full-process analysis could be executed on those static or dynamic behaviors such as temperature hysteresis, trains passing over bridge, trains braking on bridge, etc.2. The new integrative spatial model of rails-deck system-stringers-cross beams-main trusses-pier-foundation was established, adopting improved overlapping nonlinear link element to simulate the longitudinal resistance between track and bridge. In this new model, ideal elastic-plastic resistance model capable of unloading to include the influence of load history was selected, and the longitudinal resistance, transverse resistance as well as vertical stiffness were simulated. This model could represent the correlative relations among tracks, deck, transverse and horizontal girders, main trusses, supports, piers as well piles more accurately. Moreover, it could also calculate different operation conditions including single line load case and multi-line load case, and analyze the additional longitudinal forces of CWR and the track’s stability on bridges. The validity of the model in this thesis has been verified through a series of comparative analyses with those in relative codes or papers.3. The characteristics and distribution law of various longitudinal forces in the track-beam system of steel-truss arch bridge were described. The nonlinear calculations considering multi-load history and the results calculated by linear superposition method were comparatively analyzed. The influence of several sensitive factors on the longitudinal force was discussed, such as temperature combination cases, trains’ moving direction, live load model, train formation, braking force ratio, ballast resistance, stiffness of pier and abutment, layout scheme of adjacent spans, friction of movable supports and other factors. Besides, the curtailment mechanism of locating the Rail Expansion Joints (REJ), selecting the track type and the deck form, as well as setting up the Shock Transmission Unit (STU) on piers were illustrated and the optimal schemes were expounded.4. Taking the coupling of initial level irregularity and vertical profile irregularity into consideration, the track stability of CWR on the long-span steel-truss arch bridge and the transmission law of track fracture force were researched. Comparative study on the track’s instability status with track-bridge interaction or not was carried out, and sensitive research was conducted to investigate the effect of rail type, transverse resistance, vertical stiffness of railway line, and initial irregularity vector. Meanwhile, the whole transient process of track’s fracture was traced and surveyed, and the static and dynamic rail-breaking forces were compared.5. Utilizing improved Penzien model to simulate pile-soil effect, developing self-programming software to generate artificial seismic waves, the natural vibration characteristics of long-span steel-truss arch bridge considering track constraint or not were described, the seismic responses under different input modes of earthquake motion (including seismic wave’s spectral characteristics, site phase difference and so on) were studied for the track-bridge system of long-span steel-truss arch bridge. Besides, the influence law of sensitive factors such as ballast resistance, frictional effect of movable supports, layout of adjacent span, stiffness of pier and abutment were summarized, and the coupling effect of temperature, bending-braking force as well as earthquake acceleration was investigated. Additionally, some seismic applicability measures were proposed and analyzed, such as REJ, nonlinear viscous damper and track types.更多还原