以武广高速铁路无砟轨道路基典型断面现场动测为工程背景,基于FLAC3D软件建立了相邻2个转向架荷载下的无砟轨道路基三维有限差分模型,采用激振力函数模拟列车的动荷载作用.将数值模拟与现场实测结果进行对比,验证了该模型的可行性,并用该模型分析了无砟轨道路基的动应力特性.实测和模拟结果表明:基床表层顶面轨下位置动应力响应比中线处大；动应力响应在基床表层范围内最为强烈且衰减较快；列车荷载速度对动应力影响不显著.%Based on field dynamic measurements in a typical section of ballastless track subgrade in the Wuhan-Guangzhou high-speed railway,a 3D finite difference model of ballastless track subgrade under two adjacent bogies is established using the FLAC3D software.The vertical dynamic load of the train is simulated by adopting an exciting force.The model was validated through several comprehensive experiments performed in the Wuhan-Guangzhou high-speed railway.The dynamic stress characteristics of the ballastless track subgrade are discussed based on the numerical calculation results.The measured and calculated results indicate that the large dynamic stress is measured under the subgrade surface rail position,while the stress under the centre-line is small.The most intense dynamic responses are measured in the bed surface area where it reduces sharply with the increase of depth.Dynamic stress is slightly affected by the train speed.
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