活动断裂带隧道内轨道结构振动传递特性及结构选型研究

发布时间：2018-11-01 16:02

【摘要】：我国西南地区山岭密布,且生态环境比较脆弱,为了保证线路平顺性和减小列车运行对沿线环境的影响,铁路多以长大隧道的形式穿越该区域。同时,该区域分布了多个活动断裂带,往往会涉及到铁路隧道穿越活断层的情况。当列车通过时,轮轨冲击产生振动并传至隧道结构,反复作用下隧道结构会产生裂纹并不断扩展,当损伤达到一定程度时甚至导致隧道结构整体失效。同时,振动在岩土体中传播,会扰动周围岩土层,促进断层发生错动。一旦发生以上病害,将会对铁路线路和隧道结构的安全造成严重威胁。本文以成兰铁路穿越活动断裂带工程为研究背景,基于有限元理论和轮轨耦合动力学理论,进行了一系列静动力学研究,旨在为活动断裂带隧道内铁路选择合适的减振型轨道,降低轮轨振动的不利影响。论文主要工作及结论如下:(1)建立轨道-隧道-活动断裂带空间模型,采用拟静力方法模拟断层错动过程,分析断层错动下轨道结构的受力变形特性。研究表明,在断层错动条件下,无砟轨道结构出现了类似的错动变形,底座板和隧道之间出现了离缝;断层错动量达到15mm时,轨道板所受最大拉应力超过其抗拉强度,发生破坏;断层错动下,有砟轨道在受力状态、轨道结构破坏情况以及线路几何形位调整能力等方面均优于无砟轨道,建议在活动断裂带隧道内采用有砟轨道结构。(2)建立车辆-有砟轨道-隧道耦合动力学模型,从行车安全舒适性、减振效果等角度出发,分析弹性轨枕和道砟垫对系统动力特性的影响。研究表明,铺设弹性轨枕或道砟垫能保证行车的安全性和平稳性;铺设弹性轨枕明显的增大了钢轨和轨枕的垂向位移,但对降低道床动力响应作用显著;铺设道砟垫使得轨道结构位移增加的同时,也恶化了道床的工作状态;弹性轨枕和道砟垫均发挥了很好的减振效果,最大减振量分别为26dB、18dB;采用弹性轨枕或道砟垫可减缓列车冲击造成的断层错动。(3)分别改变道砟垫面刚度和弹性轨枕枕下垫层刚度,分析参数变化对车辆、轨道结构动力响应以及减振效果的影响,并据此提出参数的合理取值范围。减振垫层参数设置的原则是在控制轨道结构位移、振动以及受力的同时,不影响其减振效果,经过系统的对比分析,建议道砟垫面刚度取100～150MN/m3,弹性轨枕枕下垫层刚度取40～60MN/m。(4)提出隧道回填层采用橡胶混凝土材料的减振新思路,研究橡胶混凝土回填层的减振效果及其对车辆、轨道结构动力响应的影响。研究表明,橡胶混凝土回填层的减振效果明显,且在全频域内均有体现,衬砌的最大减振量为10.3dB;回填层采用橡胶混凝土前后,车辆、轨道结构的各动力学指标变化不大,采用橡胶混凝土回填层不会加剧轮轨动力作用和影响行车安全。
[Abstract]:The mountains in southwest China are densely distributed and the ecological environment is fragile. In order to ensure the smooth running of the railway line and reduce the impact of train operation on the environment along the line, the railway passes through the area in the form of long tunnel. At the same time, there are many active fault zones in this area, which often involve railway tunnels crossing active faults. When the train passes through, the wheel / rail shock produces vibration and transmits to the tunnel structure. Under repeated action, the tunnel structure will produce cracks and continue to expand, and even lead to the overall failure of the tunnel structure when the damage reaches a certain extent. At the same time, the vibration propagates in the rock and soil, which will disturb the surrounding rock and soil, and promote the fault dislocation. Once the above diseases occur, the safety of railway lines and tunnel structures will be seriously threatened. In this paper, based on finite element theory and wheel-rail coupling dynamics theory, a series of static and dynamic studies are carried out on Cheng-Lan railway crossing active fault zone engineering. The purpose of this paper is to select suitable vibration absorption track for railway in active fault zone tunnel. Reduce the adverse effect of wheel / rail vibration. The main work and conclusions are as follows: (1) the spatial model of track-tunnel-active fault zone is established, and the pseudo-static method is used to simulate the fault dislocation process, and the deformation characteristics of track structure under fault dislocation are analyzed. The study shows that the ballastless track structure has similar staggered deformation under the condition of fault dislocation, and the seams appear between the base plate and the tunnel. When the fault slip momentum reaches 15mm, the maximum tensile stress of the track plate exceeds its tensile strength, resulting in failure. Under fault dislocation, ballastless track is superior to ballastless track in such aspects as stress state, track structure failure and line geometric configuration adjustment ability, etc. It is suggested that the ballasted track structure should be adopted in the active fault zone tunnel. (2) the coupled dynamic model of vehicle-ballasted track and tunnel is established, which starts from the aspects of driving safety and comfort, vibration absorption effect, etc. The influence of elastic sleeper and ballast cushion on the dynamic characteristics of the system is analyzed. The research shows that laying elastic sleeper or ballast cushion can ensure the safety and stability of the train, and the laying of elastic sleeper can obviously increase the vertical displacement of rail and sleeper, but it can significantly reduce the dynamic response of track bed. The displacement of track structure is increased and the working state of track bed is worsened by laying ballast cushion, and the elastic sleeper and ballast pad play a good damping effect, the maximum damping amount is 26 dB ~ 18 dB, respectively. Using elastic sleeper or ballast cushion can slow down the fault dislocation caused by train impact. (3) the stiffness of ballast cushion and the cushion under elastic sleeper are changed respectively, and the change of parameters on vehicle is analyzed. The influence of dynamic response and damping effect of track structure is presented, and the reasonable range of parameters is put forward. The principle of setting the parameters of damping cushion is to control the displacement, vibration and force of track structure without affecting its damping effect. Through the comparative analysis of the system, it is suggested that the stiffness of ballast cushion surface should be taken at 150 MN / m ~ (3). The stiffness of the cushion layer under the elastic sleeper is 40 ~ 60 mn / m ~ (-1). (4) A new idea of reducing vibration of the tunnel backfill layer using rubber concrete material is put forward, and the effect of the rubber concrete backfill layer on the dynamic response of vehicle and track structure is studied. The results show that the damping effect of rubber concrete backfill is obvious, and it is reflected in the whole frequency domain, and the maximum damping capacity of the lining is 10.3dB; The dynamic indexes of vehicle and track structure have little change before and after the backfill layer is used rubber concrete backfill layer will not aggravate the dynamic effect of wheel / rail and affect the driving safety.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U213.21;U451

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