| With the growing national strength and people’s convenient choice of travel tools,high-speed railway in recent years is in full construction period.With the train speed of the substantial increase in the train-related track structure and roadbed foundation also raised the corresponding standard requirements.Subgrade is an important guarantee for the safe and smooth operation of the track train,supporting the upper structure.At present,both at home and abroad have started to study the environmental factors and the roadbed under the actual traffic conditions.Based on the current research situation of the high-speed railway ballastless track subgrade,this paper chooses the roadbed of Wuhan-Guangzhou high-speed railway as the research object,and establishes the corresponding simulation The numerical simulation of the model is carried out,and the numerical simulation results are compared with the measured values of the dynamic response test.Therefore,the main contents and conclusions of this paper are as follows:(1)In this paper,the simulation of the subgrade under the ballastless track is carried out,and different dynamic artificial boundaries(fixed boundary,viscous boundary,viscoelastic boundary,equivalent viscoelastic boundary and multi-layer damping boundary)are set up in the road test section.The dynamic response of the subgrade under the boundary conditions is compared with the dynamic response results under each artificial boundary,and the numerical simulation results are compared with the measured values of the field test.The results show that the multi-layer damping artificial boundary is superior to other artificial boundary conditions in numerical simulation,and the absorption of the transverse scattering wave is better,and the effect of free field can be fully achieved.With high accuracy and good stability,The rationality of the roadbed model and the loading method.It can be used to reduce the error of numerical simulation of dynamic response in subsequent numerical simulation.(2)Based on the surface of the subgrade in the ballastless track,the load of the train is considered,and the displacement and stress dynamic response of the structural layers of the subgrade are analyzed.The results show that the dynamic response of the train load is considered to be the main part of the bed load,and the influence of the dynamic response is weakened with the increase of the subgrade depth.The maximum vertical stress and equivalent stress are easily generated at the edge of the contact surface of the loading plate and the bed surface,and the stress concentration is most likely to be induced here.(3)Use the simulation model of Ballastless Track Subgrade of train loads of track irregularity under consideration in the numerical simulated calculation results of the high speed railway subgrade,to analyze the influence on dynamic response of subgrade stiffness parameters,this paper focuses on the basic body of the bottom layer of subgrade and road.The results show that the vertical structure of different layers of the subgrade dynamic stress increases with the elastic modulus of the bottom layer of subgrade decreases,but the variation is affected by the dynamic elastic modulus of embankment;and the vertical roadbed in different layers of dynamic stress increases with the embankment dynamic elastic modulus and change,the change of the law is not affected by the dynamic elastic modulus of subgrade bed.The vertical dynamic displacement of subgrade with different structure layers decreases with the increase of the dynamic elastic modulus of the subgrade and the subgrade. |
