高速铁路拱塔斜拉桥上无砟轨道隔离层变形协调性能研究

Deformation coordination performance of ballastless track isolation layer on high-speed railway arch supported tower cable-stayed bridge

为保证高速铁路大跨度桥上无砟轨道服役寿命,提高行车安全性,需对服役环境中高速铁路桥上无砟轨道隔离层变形协调性能进行研究。以高速铁路拱塔斜拉桥为工程背景,考虑桥上无砟轨道隔离层力学特性,建立拱塔斜拉桥-无砟轨道体系精细化分析模型,研究温度以及列车荷载组合作用,设置橡胶和土工布2种不同类型隔离层的拱塔斜拉桥-无砟轨道层间变形协调性能。结果表明:整体升温与索梁温差对桥上无砟轨道层间变形的影响不大,日照温度效应是引起桥上无砟轨道层间离缝的主要原因;采用土工布隔离层无砟轨道变形跟随性差,而橡胶隔离层能够有效改善桥上无砟轨道各结构层之间的变形协调性能,且体刚度较小的橡胶隔离层能有效减少层间离缝程度;温度效应以及列车荷载组合作用下,拱塔斜拉桥主梁各支承处、主梁非拉索区的无砟轨道隔离层层间变形协调性较差,均出现了轨道层间离缝现象。层间离缝最大值出现在塔梁固结区域。建议背景工程主梁拉索区CRTS-III型板式无砟轨道选用体刚度0.1 N/mm^(3)的橡胶隔离层,主梁各支承和非拉索区CRTS-III型板式无砟轨道选用体刚度0.05 N/mm^(3)的橡胶隔离层,以改善拱塔斜拉桥上无砟轨道的适用性。本文研究结论可为大跨度桥上无砟轨道的推广应用提供技术参考。

To ensure the service life of ballastless track of high-speed railway long-span bridge and improve driving safety,it is necessary to study the deformation coordination performance of ballastless track isolation layer on high-speed railway bridge in service environment.Taking the high-speed railway arch supported tower cable-stayed bridge of high-speed railway as the engineering background,considering the mechanical characteristics of ballastless track isolation layer,the refined analysis model of arch supported tower cable-stayed bridge-ballastless track system was established.The coordinated deformation performance of arch supported tower cable-stayed bridge-ballastless track layer with two different types of isolation layers,rubber and the geotextile,was analyzed under the combined effect of temperature effect and train load.The results are drawn as follows.The overall temperature increasing and the temperature difference of the cable-girder have little impact on the interlayer effect.The solar temperature effect is the primary cause of interlayer separation.The deformation followability of ballastless track with geotextile isolation layer is inferior,while the rubber isolation layer can effectively improve the deformation coordination performance between the structural layers on the bridge.The rubber isolation layer with smaller stiffness can effectively reduce the degree of interlayer separation.Under the combined effect of the temperature effect and train load,the deformation coordination performance of ballastless track isolation layers at each support and the non-tensioned area of the main girder are relatively inferior.The interlayer separation occurs.The maximum interlayer separation in the area of tower-girder consolidation.It is suggested that the rubber isolation layer is selected for background projects to improve the applicability of ballastless track on bridges:0.1 N/mm3 rubber isolation layer is selected for CRTS-III slab track laid in the cable area of the main girder.0.05 N/mm3 rubber isolation layer is selected for CRTS-III slab track laid near each supporting and non-cable area of the main girder,so as to improve the applicability of ballastless track on bridges.The results can provide technical reference for the promotion and application of ballastless track on large span bridge.