高速列车荷载作用下粗粒土填料振动变形特性分析

Analysis of Vibration Deformation of Coarse-grained Soil Filling under High-speed Train Load

路基振动变形影响列车运行安全与舒适性,开展高速列车荷载作用下粗粒土填料振动变形特性的研究具有重要意义。利用MTS加载系统和自制模型箱,构建室内粗粒土填料单元模型试验系统,模拟列车的动载作用,对粗粒土填料开展5万次循环加载试验,获得振动变形与加载次数的关系曲线,探讨动应力幅值、加载频率对振动变形的影响。结果表明,在动应力幅值为25~200 kPa、加载频率为2~8 Hz的循环荷载作用下,粗粒土填料的初始振动应变为0.0010~0.0038,5万次加载后稳定振动应变为0.0008~0.0020;振动应变与加载次数呈负幂函数关系,且随动应力幅值、加载频率的增加而增大。根据试验结果建立路基基床振动变形分析模型,验证模型的合理性。研究结果可为高速铁路粗粒土路基的振动状态评价提供参考依据。

As the vibration deformation of coarse-grained soil subgrade affects the safety and comfort of train operation,it is of great significance to study the vibration deformation properties of coarse-grained soil filling under high-speed train load.Based on MTS loading system and model box,an indoor model test system for coarse grained soil filling was constructed and the dynamic load of train was simulated.50,000 cyclic loading tests were carried out to obtain the relationship curve between vibration deformation and loading times of the coarse-grained soil filling.The effects of dynamic stress amplitude and loading frequency on vibration deformation were analyzed.The results show that under the cyclic loading with dynamic stress amplitude of 25~200 kPa and loading frequency of 2~8 Hz,the initial vibration strain of the coarse-grained soil filling is 0.0010~0.0038,and the stable vibration strain is 0.0008~0.0020 after 50,000 times of loading.The vibration strain has a negative power function relationship with loading times,and increases with the increase of dynamic stress amplitude and loading frequency.According to the characteristics of the vibration deformation curve,a mathematical formula for vibration deformation of the coarse-grained soil subgrade was proposed to verify the rationality of the model.The results of these tests can provide reference for the evaluation of the vibration state of coarse-grained soil subgrade of high-speed railway.