简支梁桥上Ⅰ型板式无砟轨道挠曲受力与变形

摘要

Research purposes:The force of CWR on bridge is very complex,the force and deformation of bridge and track structure have become a widespread concern issue.In order to study the stress,deformation and influence factors of track structure on bridge under train load,according to the structural characteristics of element slab ballastless track CWR on multi span simply supported bridge and finite element method,the space coupling model of CRTS Ⅰ slab ballastless track CWR on multi span simply supported bridge is established,the deflection force and displacement of track structure on bridge are calculated,the longitudinal resistance of fastener,longitudinal horizontal stiffness of fixed bearing of abutment and pier factors such as force and deformation influence on deflection are analyzed.Research conclusions:(1) The maximum value of deflection tension and stress appears on the left abutment fixed end and the middle of last span under the action of train load,the longitudinal displacement of rail has decreased after increasing and gradually reduced to zero on both sides of subgrade.(2) Using small resistance fastener could obviously reduce deflection force of rail and track structure,but the relative displacement of the track slab and rail will increase at the same time,rail crawling on the abutment should be focused.(3) It is disadvantageous to the longitudinal displacement of the track structure on bridge under the train load by using the low pier bridge which has large longitudinal horizontal stiffness.(4) With the increase of the number of bridge span,the longitudinal force and displacement of track structure are also increasing,and its growth trend are obvious before six-span,its growth trend slowed down and gradually stabilized after six-span.(5) The research results have reference value for the design and construction safety of CRTS Ⅰ ballastless track on bridge.%研究目的:桥上无缝线路受力比较复杂,桥梁、轨道结构的受力变形成为广泛关注的问题.为研究列车荷载作用下桥上轨道结构的受力变形规律及影响因素,根据多跨简支梁桥上单元板式无砟轨道无缝线路的结构特点,基于有限元法建立多跨简支梁桥上CRTS Ⅰ型板式无砟轨道无缝线路空间耦合模型,计算列车荷载作用下桥上轨道结构的挠曲力与位移,并分析扣件纵向阻力、墩台顶固定支座纵向水平线刚度以及桥梁跨数等因素对挠曲受力与变形的影响规律.研究结论:(1)在列车荷载作用下,钢轨挠曲拉力及压力最大值分别出现在左侧桥台固定端与最后一跨跨中位置,钢轨位移呈先增后减的趋势,并在两侧路基段逐渐减小至零;(2)采用小阻力扣件可明显降低钢轨及轨道结构的受力,但同时会增加轨板相对位移,需要重点关注钢轨在桥台处的爬行;(3)采用较大纵向水平线刚度的低墩桥对列车荷载作用下桥上轨道结构纵向位移而言是不利的;(4)随着桥梁跨数的增加,轨道结构的纵向力与位移也不断增大,在6跨之前增幅明显,6跨之后增幅明显放缓并逐渐趋于平稳;(5)本研究成果对桥上CRTS Ⅰ型板式无砟轨道的设计及结构安全性具有参考价值.