【作者】 张国忱；

【导师】 李忠献；

【作者基本信息】 天津大学 ， 结构工程， 2004， 硕士

【摘要】 列车的提速和轻轨铁路的建设加剧了车桥系统的耦合振动，而软弱地基上的基础变形更加大了此耦合振动的剧烈程度，这无疑将大幅度地降低列车的行车安全度。为了保证高速和轻轨列车的行车安全度，迫切需要对车桥系统进行耦合振动分析，并考虑基础变形对其耦合振动的影响。本文系统地进行了考虑土-结构相互作用（SSI）的车桥系统的耦合振动分析。文中首先在综合有关车桥系统耦合振动以及 SSI 分析的已有成果的基础上，系统地分析了引起车桥系统耦合振动的各种因素及其重要性，通过适当调整主要因素的影响因子而计入次要因素的影响，从而忽略次要因素而简化分析过程，最后，提出了一种考虑 SSI 效应的车桥系统耦合振动的分析方法，并采用逐步积分法求解具有时变系数的微分方程组。然后以天津轻轨工程中的一座四跨预应力混凝土连续刚构桥为例，建立了考虑 SSI 效应的车桥系统耦合振动分析的三维空间模型（其中车辆采用 27 自由度模型，梁体和桥墩采用空间梁单元，群桩基础采用等效单桩模型，桩侧土体采用弹簧和阻尼器模型），编制了相应的计算程序，数值分析了考虑 SSI 效应对车桥系统耦合振动的影响，并进一步分析了地震作用对考虑 SSI 效应的车桥系统耦合振动的影响。最后得出结论：（1）考虑 SSI 效应对于地处软弱地基的桥梁结构的动力特性将产生较大的影响，各阶自振频率较墩底固结体系均有较大的降低，因此在车桥耦合振动分析中必须考虑 SSI 效应的影响；（2）考虑 SSI 效应对车桥系统中桥梁的横桥向位移反应影响最大，对桥梁的扭转位移反应的影响也较大，而对桥梁的顺桥向位移反应和竖向位移反应的影响则很小；（3）车辆的横向摇摆力是引起车桥系统中桥梁横向振动的最主要的原因，而车辆的移动重力加载仅产生一定的影响；（4）地震作用与列车过桥两者对车桥系统中桥梁所引起的振动存在较大的耦合，不能简单地将地震反应与车桥振动反应进行叠加。更多还原

【Abstract】 The coupled vibration of train-bridge system is aggravated due to the speedingof trains and the construction of light railways, and is further intensified due to thefoundation deformation on soft soil, which will undoubtedly reduce the degree ofsafety of the train running. In order to ensure the safety of the train running on thehigh-speed railway or the light railway, it is urgent to analyze the coupled vibration ofthe train-bridge system and consider the influence of the foundation deformation onthe coupled vibration. In this thesis, the coupled vibration analysis of the train-bridge system issystemically performed considering the soil-structure interaction (SSI). Based onreviewing the current progress on the coupled vibration of the train-bridge system andthe analysis of SSI, a method for the coupled vibration analysis of the train-bridgesystem considering the SSI effect is proposed, in which all factors to induce thecoupled vibration and its importance are systemically investigated and then theprimary factors are properly augmented by ignoring the secondary factors, and theStep-by-Step Integral method is adopted to solve the quadratic differential equationswith the time-varying coefficients. Taking a four-span continuous rigid-framedprestressed concrete bridge in Tianjin light railway engineering as an example, thethree-dimensional spatial model for the coupled vibration analysis of the train-bridgesystem considering the effect of SSI is established, in which a model of train with 27degrees of freedom, the spatial beam element model for the girder and piers, aequivalent single-pile model for the grouped-piles foundation and a spring-dampermodel for the soil surrounding the piles are included. The related computer programis generated, the influence of the effect of SSI on the coupled vibration of thetrain-bridge system is numerically analyzed, and the influence of the seismicexcitation on the coupled vibration of the train-bridge system considering SSI isfurther investigated. Finally, some conclusions are given as follows. (1) The dynamiccharacteristics of the bridge on the soft soil is significantly affected by consideringthe SSI effect, in which its natural frequencies are much lower than those of thebridge with end-fixed piers, so that the SSI effect must be taken into account in thecoupled vibration analysis of the train-bridge system. (2) By considering the SSIeffect in the coupled vibration of the train-bridge system, the lateral displacement<WP=5>responses of the bridge are most intensively affected, and the rotational displacementresponses of the bridge are much intensively affected, but the longitudinal andvertical displacement responses are much slightly affected. (3) The lateral wobblingforce of the train is the foremost cause to induce the lateral vibration of thetrain-bridge system, whereas, the moving gravity force of the train is of limit effect.(4) There is a rather large degree of coupling between the vibrations of the bridgeinduced by the seismic action and the train passing the bridge, which cannot besimply superposed by the seismic responses and the responses of the coupledvibration.更多还原