市域铁路无砟轨道简支梁桥墩纵向刚度合理限值

Reasonable limits of pier longitudinal stiffness of simply supported beam bridge with ballastless track on suburban railways

基于梁-轨相互作用理论建立线-板-桥-墩空间耦合模型,研究了无砟轨道简支梁桥墩纵向刚度对钢轨附加力及断缝值的影响,给出了市域铁路简支梁桥墩纵向刚度限值的控制因素及合理值.结果表明:增大桥墩纵向刚度可减小钢轨附加总应力和梁-轨相对位移,不同于有砟轨道简支梁桥,市域铁路无砟轨道简支梁桥墩纵向刚度限值由钢轨强度控制;建议24,32,48 m简支梁桥上铺设U71Mn钢轨和常阻力扣件,温暖区域桥墩刚度限值分别取5,6和15 MN/m,寒冷区域取5,12和54 MN/m;64 m和80 m简支梁上铺设U75V钢轨和常阻力扣件,温暖区域刚度限值分别取22 MN/m和70 MN/m,寒冷区域取84 MN/m和240 MN/m;当寒冷区域80 m简支梁桥两侧梁端铺设小阻力扣件时,桥墩刚度限值可减小至84 MN/m.

Based on beam-track interaction theory,spatial coupling model of CWR-ballastless track-bridge was established,and the influence of pier longitudinal stiffness on rail additional force and rail breaking gap were studied.The control factors of pier longitudinal stiffness limit were given,and the reasonable longitudinal stiffness limit of simply supported beam bridge piers were proposed.Research results show that increasing the pier longitudinal stiffness is an effective measure to reduce the rail total additional stress and beam-rail relative displacement.Different from simply supported beam bridge which lays ballast track,when the simply supported beam bridge of suburban railways lays ballastless track,the pier longitudinal stiffness limit is controlled by rail strength.It is recommended that U71Mn rail and constant resistance fasteners can be laid on 24,32 and 48 m simply supported beam bridges,and the pier longitudinal stiffness limits of three bridges are taken as 5,6 and 15 MN/m respectively on warm region,and 5,12 and 54 MN/m on cold region.The U75V rail and constant resistance fasteners can be laid on 64 and 80 m simply supported beam bridges,the pier longitudinal stiffness limits are 22 MN/m and 70 MN/m on warm region,and 84 MN/m and 240 MN/m on cold region.On cold region,when small resistance fasteners are laid on both two beam ends of 80 m simply supported beam bridge,the pier longitudinal stiffness limit can be reduced to 84 MN/m.