In regions with large temperature differences,unit ballastless tracks are subjected to significant temperature gradients caused by solar radiation.This leads to the warping deformation of the track slabs and induces periodic irregularities on the track surface.This,in turn,increases the wheel-rail impact response of high-speed trains and accelerates damage to the track structure.To address this issue,a finite element method was adopted.First,a static analysis model of ballastless track considering interlayer relationships was established to analyze the warping deformation of the track slab and the periodic irregularities of the track surface under large temperature differences.Then,a vehicle-track system dynamics model was developed to simulate and analyze the dynamic interlayer stress characteristics of ballastless tracks under temperature differences and to study the actual service state of tracks under high-speed train operation.The results show that under the influence of temperature gradients,the track slab exhibits an elliptical deformation trend.Under a positive temperature gradient,the middle of the track slab bulges upwards with the four comers being supported,whereas under a negative temperature gradient,the four corners of the track slab lift up with the middle being supported.Temperature gradients result in varying degrees of gaps forming between the track slab and the CA mortar,reducing the contact area beneath the slab.Although the interlayer contact area gradually enlarges during high-speed train operation,the gaps do not fully close.Negative temperature gradients exerts a smaller impact on track structure vibration and mortar layer stress,while positive temperature gradients have a larger impact.When the temperature gradient reaches 90 ℃·m-1,the vibration acceleration of the track slab increases by approximately tenfold,the maximum pressure between the track slab and the CA mortar layer increases by 6.6 times,and the stress in the CA mortar at the slab comers increases by 5.4 times compared to the conditions without a temperature gradient.The significant increase in stress at the sides and comers of the track slab under positive temperature gradients is the main cause of structural damage in the CA mortar in these areas.
关键词
高速铁路/CRTS/Ⅰ型板式无砟轨道/温度梯度/周期性不平顺/层间接触/有限元
Key words
High-speed railway/CRTS Ⅰ ballastless track/Temperature gradient/Periodic irregularities/Interlayer contact/Finite element method(FEM)
万方数据