列车运行引发的黄土地区高速铁路路堑动力响应规律

Dynamic Response Law of High-speed Railway Cutting Induced by Train Operation in Loess Region

为研究列车运行状态下黄土地区路堑段路基动力响应规律,采用2.5D有限元方法对比分析了有砟轨道和无砟轨道条件下轨道位移、环境振动强度和路基动应力分布随荷载移动速度的变化规律,讨论了抗滑桩对环境振动衰减的影响。结果表明,抗滑桩改变了路基岩土介质质量和刚度分布的连续性,可有效减弱环境振动强度。无波动传播现象时,路堑不同深度处振动强度分布类似,且路基附加动应力受车速影响较小;波动传播现象出现后,随着深度的增加,路堑振动强度逐渐减小,随着车速的提高,路基附加动应力迅速增大。有砟轨道条件下的系统响应受车速影响更显著。在所涉及的黄土场地条件下,现行高铁运行速度一般不超过2种轨道结构的临界速度且不会产生波动传播现象。

The 2.5D finite element method is adopted to investigate the dynamic response of cutting subgrade in loess region under train moving load.Track displacement,environmental vibration intensity and dynamic stress of subgrade under ballast track and ballastless track conditions are obtained,and their variations along with the moving speed of train load are analyzed.Moreover,the effect of anti-slide pile on the attenuation of environmental vibration is discussed.The results indicate that the anti-sliding pile can effectively reduce the environmental vibration intensity due to its effect to change the mass and stiffness distribution continuity of the subgrade.When there is no wave propagation,the vibration intensity distribution at different depths of cutting is similar,and the additional dynamic stress of subgrade is less affected by vehicle speed.After the wave propagation appears,the vibration intensity of the cutting decreases gradually with the increase of depth,and the additional dynamic stress of subgrade increases rapidly with the increase of the train speed.The system response under the condition of ballasted track is more significantly affected by vehicle speed.Under the loess site conditions mentioned in the present study,the current high-speed railway operation speed generally does not exceed the critical speed of the two track structures,and there will be no wave propagation.