Braking Forces and Displacements of Longitudinally Counpled Ballastless Welded Turnout on Bridges
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摘要: 为系统分析纵连无砟轨道与桥上无缝道岔在制动力作用下的受力与变形规律,以武汉广州客运专线 雷大桥铺设博格纵连式无砟道岔为例,将客专18号渡线、纵连式无砟轨道、桥梁和墩台视为整体,建立了岔-板- 梁-墩一体化计算模型,分析制动力作用下道岔、道床板、桥墩的受力和变形规律.分析结果表明:在制动力作用 下,基本轨制动附加力及位移随道床板伸缩刚度的减小而增大,但板轨相对位移未超过1mm;限位器和间隔铁 的纵向力及心轨、尖轨处板轨相对位移受无砟轨道结构的影响较小,限位器未贴靠,间隔铁力最大未超过13kN; 道床板制动附加力随伸缩刚度的降低而减小,减小量最大达到3832.9kN,位移则增大,最多达到17.4mm;道 床板伸缩刚度和滑动层摩擦因数减小对桥墩受力不利;当滑动层摩擦因数u=0.2时,取消固结机构,桥墩纵向 力减小值接近500kN.Abstract: A finite element model of turnout-track slab-bridge beam-pier was established to analyze the forces exerted on ballastless track and welded turnout on bridge and their displacements under braking forces, in which a single crossover (composed of 2 sets of No.18 welded turnouts), the longitudinally coupled ballastless track, the bridge beam and the pier are regarded as one system.The welded turnout of longitudinally coupled ballastless track on Leida bridge on Wuhan-Guangzhou high speed passenger line was taken as an example. Calculation results show that braking forces on and displacement of the stock rail increase with a decrease in the slab stiffness, and the displacement between the slab and the rail is less than 1 mm. The structure of the ballastless track has a little effect on the longitudinal forces exerted on the position-limited devices and spacers, and the displacements of nose rail and switch rail. Braking forces do not result in contact between the two blocks of the position-limited device, and the forces exerted on them are less than 13 kN. A decrease in slab stiffness reduces the forces exerted on it, with a maximum value of 3 832.9 kN, and increases its displacement, with a maximum value of 17.4 mm. Decreasing slab stiffness and friction coefficient of slip layers increases the forces exerted on the piers, and when the friction coefficient is less than 0.2, the longitudinal forces exerted on the piers decreases by about 500 kN.
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