高速铁路斜拉桥与无缝线路相互作用研究

Interaction between cable-stayed bridge traveled by high-speed trains and continuously welded rail

为研究高速铁路斜拉桥与无缝线路的相互作用问题,采用非线性杆单元模拟梁轨接触,并与UIC算例对比以验证其正确性。以沪昆线上某(32+80+112)m槽形截面独塔斜拉桥为例,建立考虑桥塔、拉索、主梁、轨道以及相邻桥跨的高速铁路斜拉桥梁轨相互作用模型,系统地分析温度、活载、列车制动、风载、混凝土收缩徐变以及地震作用下斜拉桥上无缝线路纵向力及墩顶水平力的分布规律,并对设计参数的影响进行探讨。在荷载组合方面,采用考虑加载历史的荷载步法与传统的数值相加方法进行对比。得出的主要结论包括:对钢轨来说,斜拉桥两端及桥台处钢轨受力较大,采用固结体系可大幅度减小钢轨挠曲和制动力,收缩徐变和地震荷载对钢轨纵向力影响较大,地震动的行波效应会增大桥台处的钢轨应力;对桥梁下部结构而言,挠曲力、制动力和地震力主要由桥塔承受,温度和收缩徐变产生的水平力主要由斜拉桥两端交接墩承受;在检算钢轨纵向力时,可采用数值相加的方法,但在检算桥墩时采用考虑加载历史的荷载步法更为安全。

To study the interaction between cable-stayed bridge traveled by high-speed trains and CWR （Continuously Welded Rail）, nonlinear bar elements were used to simulate the track-bridge contact, and then the numerical simulation was compared with the UIC example to verify its correctness. Taking the （ 32 ＋ 80 ＋ 112 ） m single-tower cable-stayed bridge with U-shape section on the Shanghai-Kunming line as an example, a model was established by considering tower, cable, girder, track and neighboring structures. The distributions of the longitudinal forces of CWR and the horizontal forces at the top of piers were systematically analyzed under the actions of bending, braking, thermal effect, wind, shrinkage and creep as well as earthquake, and furthermore the design parameters were discussed. In the load combination method, the ＂step-by-step analysis＂ with the loading history considered was compared with the traditional ＂simple summation＂ method. The following conclusions are obtained： The track stresses at both ends of the cable-stayed bridge and at the bridge abutment are larger. The bending and braking force of rails may be significantly reduced by using the consolidation system. The shrinkage creep and seismic load have the greater influences on the longitudinal force of the track and the traveling wave effect of the earthquake motion can increase the track stress at the bridge abutment. For the substructure of bridge, the bending force, braking force and seismic force are mainly withstood by the tower, while the horizontal forces produced by the temperature and shrinkage creep are mainly taken by the piers at both ends of the cable-stayed bridge. When checking the longitudinal forces of the track, the simple summation method may be used, but when checking the piers, the loading step-by-step analysis with the loading history considered should be safer.