高速列车气动力作用下跨线铁路斜拉桥及桥上轨道结构的动力响应

Dynamic Response of Fly-Over Cable-Stayed Bridge and Bridge Deck Track Structure under Aerodynamic Force of High-Speed Train

将列车高速运行产生的空间流场视为黏性、可压缩的非定常流,采用滑移网格法建立高速列车和跨线预应力混凝土斜拉桥流场模型,分析列车分别以350和500km·h-1速度从距离轨面高7.25m的预应力混凝土斜拉桥下穿过时该跨线桥受到的气动力影响。基于建立的合拢阶段斜拉桥、运营阶段斜拉桥—轨道系统的空间分析模型,分析高速列车气动力引起的跨线斜拉桥及桥上无缝线路的动力响应。研究表明,高速列车尾流对斜拉桥的气动力作用大于列车头,列车正上方梁体所受气动力最大;列车气动效应对合拢阶段斜拉桥位移影响极小;考虑轨道结构后,斜拉桥横向位移和扭转略有增大,列车气动力引起的跨线斜拉桥上钢轨应力和横向变形最大值分别为0.18MPa和0.28mm,剪力卡榫及桥塔所受横向力最大值为158kN。

The spatial flow field generated by high-speed train was regarded as a viscous, compressible and unsteady flow. The sliding mesh method was adopted to establish the flow field model/or high-speed train and fly-over prestressed concrete cable-stayed bridge. When 350 and 500 km h-1 train passed under the prestressed concrete cable-stayed bridge of 7.25 m high away from the rail surface respectively, the aero- dynamic influence on the fly-over bridge was analyzed. On the basis of the spatial analysis model for the cable-stayed bridge in the closure phase, cable-stayed bridge and track system in the operation phase, the aerodynamic response of both the fly-over cable-stayed bridge and bridge deck continuously welded rail under the aerodynamic force of high-speed train was analyzed. The study shows that the effect of high-speed train tail flow on the aerodynamic force of cable-stayed bridge is greater than that of train head flow, and the aerodynamic force applied to the beam body right above the train is the maximum. The train aerodynamic effect on the displacement of cable-stayed bridge is minimal in the closure phase. Considering the track structure, both the lateral displacement and torsion of cable-stayed bridge slightly increase. The maximum rail stress on the fly-over cable-stayed bridge and the lateral deformation induced by the aerodynamic force of train is 0. 18 MPa and 0.28 mm respectively, and the maximum lateral force applied to the shear clips and bridge tower is 158 kN.