板式无砟轨道路基翻浆整治效果研究

Study on Injection-repaired and Reinforcement Effects of Subgrade Frost Boiling under Ballastless Track

基床翻浆引起无砟轨道路基不均匀沉降,降低线路平稳性,影响高速铁路行车安全,一般采用注胶工艺对其进行整治。为评价基床翻浆段板式无砟轨道路基注胶整治效果,在沪宁城际路基翻浆工点进行现场行车测试试验,基于动力学响应指标分析方法研究基床翻浆注胶前后无砟轨道路基振动特性。结果表明:基床翻浆导致底座板与基床表层接触状态劣化,并改变无砟轨道路基的支承条件及传力路径,使振动能量垂向传递在底座板-路基面结构层间衰减较多;注胶加固后,轨道板和底座板振动位移、振动加速度、振动速度值大幅减少。其中,底座板是受注胶加固影响较大的结构层,其振动减小较大,列车以速度280km/h通过时,动位移均值从0.31mm减至0.16mm,减少48.4%;振动加速度均值从3.44m/s2减至1.13m/s2,减少67.2%。以上数据表明注胶后路基与底座板接触状态明显改善,路基已恢复参振耗能功能和对无砟轨道的支承作用,且振动波垂向衰减速率变大,列车速度对无砟轨道路基振动特性影响变小,注胶整治效果良好。

The uneven settlement of ballastless track subgrade caused by subgrade frost boiling reduces track stability and affects the safety of train operation, which is repaired with the technology of injecting chemical glue. In order to evaluate the remedial effect, in-situ train-induced vibration tests were carried out in the section of Shanghai-Nanjing intercity railway where frost boiling occurred. Based on dynamic response index analysis method, the vibration characteristics of the ballastless track subgrade under the conditions of frost boiling and injection-repaired reinforcement were analyzed. The results showed that the subgrade frost boiling caused dete- rioration of contact status between the base plate and the subgrade surface layer and changed force transmission path and bearing conditions of the subgrade, which further caused more attenuation of vertical transfer of vibra tion energy between the base plate and the subgrade layer. After the iniection of chemical glue, the vibration displacement, the vibration acceleration and the vibration velocity value of the track plate and the base plate greatly reduced. In the structure, the base plate was affected more by the injection, with significant vibration reduction. When the train speed reached 280km/h, the mean value of the dynamic displacement of the base plate decreased by 48.4%, from 0. 31mm to 0.16mm, and the vibration acceleration of the base plate decreased by 67. 2%, from 3.44 m/s2 to 1. 13 m/s2. The above data indicated that the contact state between the base plate and the subgrade layer has greatly improved after the injection. The role of supporting for ballastless track and the function of vibration energy dissipation of the subgrade have been restored. While the vertical at tenuation of the vibration wave increased, the influence of the train speed on the vibration characteristics of the ballastless track subgrade became small, proving prominent injection-repaired effect.