应用有限元方法建立土质路基上 CRTS III 型板式无砟轨道系统空间耦合模型，研究路基不均匀沉降作用下板式轨道的受力和变形特性，以及路基发生不均匀沉降时底座板和路基表层之间接触应力和脱空区域的变化规律。结果表明：路基发生不均匀沉降时，无砟轨道结构在重力作用下会发生跟随性变形；轨道板、自密实混凝土和底座板在路基沉降作用下的应力受路基沉降波长和幅值的综合影响，路基沉降幅值越大，轨道各层受力越大，波长为20～30 m 的路基沉降对轨道应力的影响较大；底座板和路基表层间的接触应力和脱空区域随着路基沉降幅值的增大而增大，随着路基沉降波长的增大出现先增大后减小的变化趋势。由此可见，路基不均匀沉降会对轨道结构的受力和变形产生明显影响，严重时会造成轨道脱空，对行车安全舒适性产生较大影响，应加以严格控制。%A spatial coupled dynamic model of CRTS III slab track system on the soil subgrade was established based on the finite element method.The stress and deformation characteristics of the slab track under the influ-ence of subgrade settlement were studied,and the variations of the contact stress and cavity area between the supporting layer and the subgrade surface were analyzed when the uneven settlement occurs.Results indicate that:the layers of non -ballast track structure deform accordingly with the subgrade settlement under gravity. The stresses of the track slab,self -compacting concrete layer and supporting layer are affected comprehensively by the wavelength and amplitude of the subgrade settlement.The slab stress would increase when the amplitude of the subgrade settlement rises,and the subgrade settlement with wavelength between 20 ~30 m has a greater influence on the slab stress.An increase in the subgrade settlement amplitude would lead to larger cavity areas and contact stresses between the supporting layer and the surface of subgrade.Meanwhile the cavity areas and contact stresses show a trend of first increasing and then decreasing as the wavelength increases.It can be seen that the uneven subgrade settlement has a significant influence on the track stress and deformation,even causes track layer gaps,all of which will worsen the riding comfort and running safety of the vehicle.Therefore it is nec-essary to take a good control of the uneven subgrade settlement.
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