桥上CRTSⅡ型板式轨道裂缝及钢筋锈蚀时变规律

Monitoring of the evolution of crack and steel bar corrosion of CRTS Ⅱ slab trackon bridge

建立一套长期监测系统,监测桥上CRTS Ⅱ型板式无砟轨道温度场、典型裂缝及钢筋锈蚀速率的时变规律。研究结果表明:轨道板和底座板的缝宽日变化幅度分别为0.2 mm和0.1 mm,缝宽均随温度的降低呈规律性增长,底座板缝宽变化幅度明显低于轨道板,这与无砟轨道温度场分布情况一致。2 a的钢筋锈蚀速率的监测数据表明,虽然内部钢筋锈蚀速率较低,但表现出一定增长规律,若不及时进行修补,难以保证无砟轨道达到其设计寿命。

A monitoring system was installed in CRTS II slab track on bridge in this study, which can monitor the track temperature field, the typical crack change rules and internal steel bar corrosion rate. The results show that the crack daily variations of the slab and base are about 0.2 mm and 0.1 mm respectively. The crack width of the slab and base increased with the decrease of temperature. The change of the base crack is obviously lower than that of the slab, which is consistent with the temperature field distribution of the slab track. The monitoring data of the steel corrosion rate of two years indicates that in spite of the low corrosion rate of the internal steel, the corrosion rate increases with time. If the crack is not repaired timely, the design service life of ballastless track will not be secured.