Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynam...Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS Ⅲ slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS Ⅲ slab track.展开更多
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...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。展开更多
Good interlayer interface performance is the key to maintaining the stability of CRTSⅡslab ballastless track structure.In a project,the tangential cohesion parameters of CRTSⅡslab ballastless track structure are gen...Good interlayer interface performance is the key to maintaining the stability of CRTSⅡslab ballastless track structure.In a project,the tangential cohesion parameters of CRTSⅡslab ballastless track structure are generally measured by horizontal push plate test,so as to measure the interlayer interface performance.Horizontal push plate contraction scale and full scale tests of CRTSⅡslab ballastless track structure are carried out to obtain the tangential force-displacement relation curve of the interlayer interface,thus obtaining the parameters of cohesion model.A threedimensional progressive damage analysis model for CRTSⅡslab ballastless track structure is established,the whole process inversion of the horizontal push plate test is carried out,and the reliability of the contraction scale test results is verified by means of simulation and comparative analysis of test results.The results show that the greater the tangential stiffness of the interlayer interface of the track structure,the weaker the interlayer deformation coordination capability;the more significant the non-uniformity of the interface damage,the more likely the stress concentration;the greater the fracture toughness,the less likely the disjoint in the interlayer interface of the track structure.展开更多
基金supported by National Key R&D Program of China[Grant No.2022YFB2603400]R&D Project of China State Railway Group Corporation Limited[Grant No.P2021G053]R&D Project of China Academy of Railway Science Corporation Limited[Grant No.2023YJ200].
文摘Purpose-Temperature is an important load for a ballastless track.However,little research has been conducted on the dynamic responses when a train travels on a ballastless track under the temperature gradient.The dynamic responses under different temperature gradients of the slab are theoretically investigated in this work.Design/methodology/approach-Considering the moving train,the temperature gradient of the slab,and the gravity of the slab track,a dynamic model for a high-speed train that runs along the CRTS Ⅲ slab track on subgrade is developed by a nonlinear coupled way in Abaqus.Findings-The results are as follows:(1)The upward transmission of the periodic deformation of the slab causes periodic track irregularity.(2)Because of the geometric constraint of limiting structures,the maximum bending stresses of the slab occur near the end of the slab under positive temperature gradients,but in the middle of the slab under negative temperature gradients.(3)The periodic deformation of the slab can induce periodic changes in the interlayer stiffness and contact status,leading to a large vibration of the slab.Because of the vibration-reduction capacity of the fastener and the larger mass of the concrete base,the accelerations of both the slab and concrete base are far less than the acceleration of the rail.Originality/value-This study reveals the influence mechanism of temperature gradient-induced periodic deformation in the dynamic responses of the train-track system,and it also provides a guide for the safe service of CRTS Ⅲ slab track.
文摘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。
文摘Good interlayer interface performance is the key to maintaining the stability of CRTSⅡslab ballastless track structure.In a project,the tangential cohesion parameters of CRTSⅡslab ballastless track structure are generally measured by horizontal push plate test,so as to measure the interlayer interface performance.Horizontal push plate contraction scale and full scale tests of CRTSⅡslab ballastless track structure are carried out to obtain the tangential force-displacement relation curve of the interlayer interface,thus obtaining the parameters of cohesion model.A threedimensional progressive damage analysis model for CRTSⅡslab ballastless track structure is established,the whole process inversion of the horizontal push plate test is carried out,and the reliability of the contraction scale test results is verified by means of simulation and comparative analysis of test results.The results show that the greater the tangential stiffness of the interlayer interface of the track structure,the weaker the interlayer deformation coordination capability;the more significant the non-uniformity of the interface damage,the more likely the stress concentration;the greater the fracture toughness,the less likely the disjoint in the interlayer interface of the track structure.
