高速铁路无砟轨道混凝土疲劳性能试验制度

Fatigue Performance Test System for Ballastless Track Concrete of High Speed Railway

根据无砟轨道混凝土实际荷载状态,采用两参数Weibull分布函数分析了疲劳试验制度关键参数对混凝土疲劳性能的影响规律。结果表明:以弯曲疲劳形式加载时混凝土疲劳性能变化显著,且无砟轨道在弯曲疲劳下更易发生疲劳破坏;加载频率越高混凝土疲劳寿命离散性越大,加载频率在5~15 Hz时混凝土疲劳寿命受加载频率影响不明显;应力水平为0.6时混凝土疲劳寿命离散性最小;以等幅正弦波加载时疲劳寿命略短于以变幅组合波加载时,但其离散性更小。综合考虑加载幅值、设备要求、试验效率、试验结果的准确性等,建议无砟轨道混凝土疲劳试验制度为:采用弯曲疲劳+等幅正弦波加载,加载频率20 Hz,应力水平0.6,应力比0.1。

According to the actual load state of ballastless track concrete,the influence laws of key parameters of fatigue test system on the fatigue performance of concrete were analyzed by using two parameter Weibull distribution function.The results show that the fatigue performance of concrete changes significantly under bending fatigue loading,and ballastless track is more prone to fatigue failure under bending fatigue.The higher the loading frequency is,the greater the dispersion of concrete fatigue life will be.When the loading frequency is 5~15 Hz,the fatigue life of concrete is not significantly affected by the loading frequency.When the stress level is 0.6,the dispersion of concrete fatigue life is the smallest.The fatigue life under constant amplitude sine wave loading is slightly shorter than that under variable amplitude combined wave loading,but its dispersion is smaller.Considering comprehensively the loading amplitude,equipment requirements,test efficiency,accuracy of test results,etc.,it is suggested that the fatigue test system of concrete for ballastless track should be bending fatigue+constant amplitude sine wave loading,where the loading frequency is 20 Hz,the stress level is 0.6,and the stress ratio is 0.1.