【作者】 张英杰；

【导师】 凌贤长；

【作者基本信息】 哈尔滨工业大学 ， 建筑与土木工程（专业学位）， 2020， 硕士

【摘要】 针对目前高铁路基动力响应评价指标单一、研究内容不够全面且多集中在非冻土地区等现状,本文以高速列车振动荷载下深季节冻土区铁路路基为主要研究对象,综合使用现场监测、数值模拟及理论分析等多种研究方法,对路基和场地动力响应的分布特征、传播规律及衰减特性等进行较为系统的研究,主要研究内容及结论如下:首先,在哈尔滨–佳木斯快速客运专线典型断面处开展了冻结期和正常期高铁有砟轨道路基振动响应的现场监测,分析了各测点竖向振动响应的时程曲线特征、幅值衰减规律及频谱分布特性,并研究了列车运行速度、季节变化对于路基振动响应幅频特性的影响。其次,基于车辆–轨道–路基耦合动力学理论,在有限元软件中利用Python语言参数化建立了包含多节编组的车辆–轨道–轨枕–道床垂向耦合模型,获取了列车经过时的轨枕作用力。通过与秦沈客运专线现场实测数据的对比,验证了模型的可靠性。然后,根据已有资料,针对深季节冻土区铁路路基,建立了考虑相变的非稳态温度场有限元模型,温度场模拟结果表明:在深季节性冻土区,路基内部温度场会随着四季交替而发生改变,由于土体传热性质的差异,路基内温度的传播具有明显的滞后性;根据路基内部温度场及冻融状态的差异,季节性冻土区路基可分为正常期、冻结期和融化期。最后,在上述工作的基础上,利用热力间接耦合法,进行温度和列车振动荷载下路基动力响应的研究工作。分析了季节变化、列车荷载类型、荷载幅值、列车速度等因素对于路基动力响应分布特征、衰减规律及幅频特性的影响,并就各项动力响应的传播及衰减规律展开探讨。研究结果表明,不同冻融时期土体力学性质的不同会使路基动力响应的幅频特性产生较大差异;相较于单车荷载,双车荷载下路基内部各项动力响应的幅值较单车荷载时均有所增加,但增长幅度存在较大区别,这在路基表层表现的尤为明显;路基竖向振动加速度、速度、位移、动应力等动力响应指标在多因素影响下的变化规律不同,传播及衰减特性也存在较大差异。本文的研究结论可进一步加深对季节性冻土区高铁路基动力响应的认识,并为季节性冻土区铁路路基的设计施工、行车组织设计、铁路及地铁沿线场地环境振动的预测评估以及精准化减隔振措施的发展提供参考。更多还原

【Abstract】 At present,the dynamic response evaluation index of high-speed railway subgrade is single,the research content is not comprehensive,and most of them are concentrated in unfrozen region.In order to study the distribution characteristics,generation mechanism,propagation law of dynamic response of subgrade,this article takes the railway embankment in deep-season frozen region under the vibration load of high-speed trains as the main research object,comprehensively using a variety of research methods such as field monitoring,numerical simulation and theoretical analysis.The main research content and conclusions are as follows:Firstly,at the typical section of Harbin-Jiamusi high-speed railway,the field monitoring of vibration response of ballasted track subgrade during frozen and unfrozen periods was carried out.Based on the monitoring data,the characteristics of the time-history curve,the law of amplitude attenuation and the spectrum distribution characteristics of the vertical vibration acceleration at each measuring point were analyzed,and the influence of the speed and seasonal changes on the amplitude-frequency characteristics of the subgrade vibration response was studied.Secondly,based on the coupling dynamics theory,the vehicle-track-sleeper-track bed vertical coupling model with multi-section grouping is established in the finite element software using Python and then obtain the sleeper force when the train passes by.Later,the reliability of the model is verified by comparison with the field measurement data of the Qin-Shen high-speed railway.Thirdly,according to the relevant data,the unsteady temperature field finite element model considering the phase change is established for the railway subgrade in the deep seasonal frozen region.The temperature field simulation results show that: in the deep seasonal frozen region,the temperature field inside the subgrade changes with the alternation of four seasons,because of the difference of the heat transfer property of the soil,the temperature propagation in the subgrade has obvious hysteresis.According to the temperature field inside the subgrade and the freeze-thaw state,the subgrade in seasonally frozen region can be divided into normal period,frozen period and melting period.At last,the indirect coupling method of thermology and mechanics was used to study the transient dynamic problems under train load.According to the model,the influence of seasonal variation,train load type,train load amplitude,train speed on the distribution characteristics,attenuation law and amplitude frequency characteristics of subgrade dynamic response are analyzed,and the propagation law of each dynamic response are discussed,as well.The results show that the different mechanical properties of soil in different frozen period make the amplitude frequency characteristics of subgrade dynamic response different greatly;Compared with the single vehicle load,the dynamic response amplitude of the subgrade under the double vehicle load is increased,but the increase amplitude is quite different,especially in the surface layer of the subgrade;The vertical acceleration,velocity,displacement and other dynamic response indexes of subgrade are caused by different frequency components in the vibration wave,so there are obvious differences in the attenuation law in the process of transmission to the outside.The conclusion of this article can further deepen the understanding of the dynamic response of the high-speed railway subgrade in the seasonal frozen region.,and provide reference for the design and construction of railway subgrade in seasonal frozen region,traffic organization design,prediction and evaluation of site environmental vibration along railway and subway,as well as the development of accurate vibration reduction and isolation measures.更多还原