中文摘要：

大跨度混凝土桥梁结构型式在我国高速铁路中被广泛采用，但铺设无砟轨道的极限温度跨度成为困扰桥上Ⅱ型板式轨道的设计难题。根据桥上Ⅱ型板式轨道结构特点，建立桥上Ⅱ型板式轨道线一板一桥一墩非线性空间一体化模型，并在有限元软件ABAQUS中建立对应的有限元模型，探索不同荷载工况作用下，轨道结构受力和变形随温度跨度增长的特点，并运用桥上无缝线路设计理论和极限状态法对轨道结构进行检算。研究结果表明：随着温度跨度的增长，轨道结构受力有不同程度的增长，荷载工况中桥梁伸缩影响最大。当温度跨度达到496m时，钢轨、轨道板检算均满足要求，但此时底座板已达到正常使用极限状态的控制条件。因此，建议用于铺设Ⅱ型板式轨道的大跨连续梁桥温度跨度不宜大于496m。

英文摘要：

Although the structure of large span concrete bridge is widely used in China high -speed railway, the critical expansion length of large span concrete bridge still remains uncertain during the design of CRTS Ⅱslab track on bridge. The nonlinear spatial rail - slab - bridge - pier integrated mechanical model was established based on the characteristics of CRTSⅡ slab track on bridge. And the corresponding finite element model was established in finite element software ABAQUS. With the increasing of expansion length, the stress and deforma- tion characteristics of the track structure were studied under different load cases. Both the design theory of CWR on bridge and limit state method were used to track structure check -calculation in force and deformation. The result shows that different track structure has different degrees of growth with the increasing of expansion length. Among the load cases, contractility caused by bridge temperature has a greater influence. When the expansion length reaches 496m, the stress and deformation of the rail and track slab are not achieved the limitations, but the concrete underlayer has reached the serviceability limit state at this time. Therefore, it is suggested that the ultimate expansion length of the large span continuous beam bridge used for laying the CRTSⅡ slab track should not be greater than 496 m.