大跨度斜拉桥—无砟轨道结构变形适应性研究

以某高速铁路客运专线上铺设CRTSⅠ型双块式无砟轨道的大跨度斜拉桥为例,采用非线性阻力模型模拟扣件阻力、凸型挡台咬合力、隔离层摩擦阻力,基于有限元法建立无砟轨道—桥梁空间精细化非线性分析模型。通过计算列车竖向荷载和温度荷载作用下轨道结构和桥面板的竖向变形曲率、无砟轨道层间压缩量和梁端转角,分析无砟轨道与大跨度斜拉桥间的变形适应性。结果表明:列车竖向荷载在斜拉桥中跨时会引起各构件产生较大的竖向变形曲率;同一工况下轨道结构和桥面板竖向变形曲率的分布规律相同、数值大小相近;相比于列车竖向荷载,温度荷载作用下各结构竖向变形曲率较小,但分布更为复杂;除整体升温、整体降温作用下结合段无砟轨道出现局部层间脱空外,荷载作用下无砟轨道层间基本处于受压状态;梁端转角均未超过规范限值,具有较高安全富余度。

Deformation Adaptability of Long-Span Cable-Stayed Bridge and Ballastless Track Structure

Taking a long-span cable-stayed bridge with CRTSⅠdouble- block ballastless track on the passenger dedicated line of a high- speed railway as an example, a refined nonlinear analysis model for the spatial interaction of ballastless track and bridge was established based on finite element method, by using nonlinear resistance models to simulate the resistance of fastener, the restraint of shear cam and the friction resistance of isolation layer. The deformation adaptability between ballastless track and long-span cable- stayed bridge was analyzed by calculating the vertical deformation curvature of track structure and bridge deck under the vertical load and temperature load of train, the interlayer compression amount of ballastless track and the rotation angle at beam end. Results indicate that, when the vertical load of train is in the midspan of cable-stayed bridge, it will cause each structure to have larger vertical deformation curvature. The vertical deformation curvatures of track structure and bridge deck under the same condition are similar in distribution rule and value. Compared with the results under train vertical load, the vertical deformation curvature of each structure under temperature load is smaller in value, but more complicated in distribution. Except that the local interlayer void occurs at the joint section under temperature rising and temperature dropping conditions, the interlayer of ballastless track is always compressed under loads. The rotation angles at beam end do not exceed the limit values in relative codes and have higher safety redundancy.