桥梁温度跨度对双块式无砟轨道无缝线路的影响研究

为研究桥梁温度跨度对桥上双块式无砟轨道无缝线路的影响,运用线板桥墩一体化模型,计算不同温度跨度下,分别采用常阻力和小阻力扣件时的钢轨纵向力、道床板纵向力、抗剪凸台纵向力、梁轨相对位移以及钢轨断缝,分析桥梁温度跨度对轨道结构强度与变形的影响。结果表明:(1)随着桥梁温度跨度的增加,钢轨伸缩、挠曲、制动附加力和梁轨相对位移均增大;道床板、抗剪凸台纵向力和钢轨断缝保持不变。(2)扣件阻力减小时,轨道结构纵向力均减小;但梁轨相对位移和钢轨断缝增大。(3)为保证钢轨强度要求,当桥上铺设常阻力扣件时,桥梁温度跨度限值可取135m;当桥上铺设小阻力扣件时,桥梁温度跨度限值可取250m。

Research on Effects of Bridge Temperature Span on Continuous Welded Rail and Double Block Ballastless Track

In order to study the effects of bridge temperature span on continuous welded rail and double block ballastless track, a line-slab-bridge-pier integration model is established to calculate the longitudinal force of the rail,the longitudinal force of the track slab,the longitudinal force of the shear cam,relative displacement between bridge and rail,and rail cracks with constant resistance and small resistance fasteners at different temperature span,and analyze the impact of bridge temperature span on the strength and stability of track structure. The results show that( 1) with the increase of temperature span,the additional longitudinal force of the rail and relative displacement between bridge and rail all increase,but the longitudinal force of the track slab and shear cam and rail cracks stay unchanged;( 2)when the fastening resistance decreases,the longitudinal forces of track structure all decrease,but the relative displacement between bridge and rail and rail cracks increase;( 3) in order to ensure the strength of the rail,when the fasteners with constant resistance are installed,the limit of temperaturespan may reach 135 m; when the fasteners with small resistance are fixed,the limit of temperature span can reaches 250 m.