【作者】 赵曼；

【导师】 阎贵平； 钟铁毅；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2008， 博士

【摘要】 板式无碴轨道以其稳定性好、耐久性强和少维修等特点在国内外得到了广泛应用。轨道板是板式无碴轨道的重要组成部分,一般采用钢筋混凝土结构,由于普通混凝土的力学性能较差,钢筋容易锈蚀等缺陷,影响了无碴轨道的发展。活性粉末混凝土(Reactive Powder Concrete,简称RPC)是一种新型混凝土材料,与普通混凝土相比,具有超高强度、高韧性、高耐久性等特点,尤其是其良好的抗拉性能,可以使结构在不配置钢筋条件下满足相同的使用要求。将RPC材料应用于板式轨道,必然可以弥补普通混凝土板式轨道的不足,改善板式无碴轨道结构的性能。基于以上原因,本文对RPC板式轨道的设计理论与力学性能进行了细致深入的研究,主要的研究工作如下:(1)基于RPC的优越性,并考虑普通混凝土实体型轨道板的受力特点,结合国内外轨道板的设计型式,提出了RPC实体型、格构型和框架型等轨道板的初步设计方案。采用ANSYS全结构仿真分析技术,建立了不同类型板式轨道结构的三维有限元模型。通过对其力学性能、经济性能、工艺性能等方面的对比分析,提出RPC板式轨道结构的最优型式为变厚度的框架型板式轨道结构。(2)由于RPC具有较高的抗拉强度和弹性模量,基于强度和刚度准则的设计原则不再适合于RPC板式轨道结构。针对RPC板式轨道结构,提出了其设计应在满足强度和刚度的前提下,充分考虑结构的弹性性能。并进一步对RPC板式轨道的设计参数进行了详细的分析,确定了RPC变厚度框架型轨道板的设计尺寸,给出了其它设计参数的建议值。(3)框架型轨道板的应力在宽度方向分布不均匀,掘此在轨道板中引入了有效工作宽度的概念,并提出在采用弹性地基梁理论时,梁的宽度应取轨道板的有效工作宽度而不是实际宽度。根据轨道板的结构特点和受力特点,提出了RPC变厚度框架型轨道板的计算模型为弹性地基框架梁模型,同时基于静力平衡和变形协调条件,给出了RPC框架型轨道板的计算方法。(4)根据RPC的材料特性以及RPC构件的破坏特征,详细分析了RPC轨道板的破坏过程及其各阶段的应力特征,确定了RPC轨道板的破坏模式只能为受拉破坏,给出了破坏时的应力分布图和简化应力计算图,提出RPC轨道板按极限状态法进行设计和计算的方法。(5)提出RPC板式轨道结构的计算模型为多层弹性地基梁模型。根据RPC框架型轨道板的弹性地基框架梁理论,可以将结构分解为纵向和横向两部分单独进行计算。建立了适用于RPC板式轨道的设计理论和计算方法,并利用Fourier变换得到了RPC框架型板式轨道结构动力学方程的解析解,对传统的计算方法和求解方法进行了改进与修正。(6)采用有限元法研究了桥上RPC板式轨道的动力性能。视板式轨道、桥梁、移动荷载为一系统,运用弹性系统动力学总势能不变值原理和“对号入座”法则,建立了系统的振动方程组,通过自编程序研究了系统的动力性能,结果表明:与普通板式轨道结构相比,RPC框架型板式轨道在动力性能方面具有明显的优越性。更多还原

【Abstract】 For the good stability,high durability and less maintenance of slab track it has been widely used at home and abroad.The slab is the most important part of slab track.At present it usually uses reinforced concrete structure.As mechanical property of common concrete is poor,and the reinforcement is apt to be rusted,etc,all these factors have affected development of slab track.Comparing with common concrete,reactive powder concrete(RPC) possesses more welcome properties such as ultra-high strength, high toughness,and high durability and so on.So if RPC is applied to slab track it can meet the same operating requirements without reinforcements,and make up for the shortcomings of common concrete slab track and improve its performances.Based on the reasons above,the design theory and mechanical property of RPC slab track will be studied deeply in this dissertation.The research works are as follow:(1) Based on the advantages of RPC,considering the stress characteristics of common concrete solid slab and design types of slab in domestic and abroad,the paper has given several preliminary design schemes such as RPC solid,grid and frame,etc.Using ANSYS simulation techniques for entire structure,the paper has built 3D finite element models for slab track of different types.By comparatively analyzing the mechanical behavior,economic performance and technological property,etc,it puts forward that slab track with frame type and variable thickness is the optimal type for RPC slab track.(2) As tensile strength and elastic modulus is higher,the criterion based on strength and stiffness is no longer suitable for RPC slab track.During the design about RPC slab track,elastic design principle should be fully considered on the premise of strength and stiffness.Following this principle design parameters of RPC frame slab track have been analyzed in great detail.The design drawing of RPC frame slab with variable thickness is determined and the suggested values of other design parameters are given also.(3) For the stress along width of frame slab track is unequal,the concept of effective working width is introduced into slab.It is proposed that the beam width should be the value of effective working width but not the whole width of slab when the theory of beam on elastic foundation is used.According to structural and stress characteristics of RPC slab,the model of frame beam on elastic foundation is proposed to be the calculation model of RPC frame slab.Based on the condition of static equilibrium and deformation compatibility,its calculation method is proposed also. (4) According to material properties of RPC and failure characteristics of RPC members, it is detailed to analyze the failure process and stress charateristic of each stage.It is determined that the failure mode of RPC slab can only be tension-destroying.The stress distribution graph and simpified stress graph are given,and according to them the limit state design and calculation mothod are put forward.(5) It is proposed that calculation model of RPC slab track is multi-layer beams model on elastic foudation.According to the theory of frame beam on elastic foudation,the RPC slab track model can be decomposed into longitudinal and transverse parts and then calculated respectively.It puts forward the design theory and calculation method which are suitable for RPC slab track.With the help of Fourier transform,analytical solution on dynamic equations of slab track is obtained,and conventional calculation method and solving method have been improved and modified.(6) A finite element method is applied to analyze the dynamic response of RPC slab track.The slab track,beam and moving load are regarded as a system.Vibration equations of the system are formulated by using the principle of total potential energy with stationary value in elastic system dynamics and the rule of "set-in-right-position". Dynamic performance is studied through self-compiling programm.The results indicate that the RPC slab track is much better than common slab track in terms of dynamic performance.更多还原