Research On Transverse Mechanical Characteristics Of Ballasted Track Structure Under Stable Operation

The lateral resistance of the ballast bed is one of the key evaluation indicators for the quality of the ballast bed,which is very important for maintaining the lateral stability of the ballasted track.Existing ballast bed lateral resistance detection methods are mainly performed offline.The implementation process is complicated and inefficient.As a result,the staff cannot timely and accurately grasp the ballast bed lateral resistance after stabilizing the car,which leads to the occurrence of ballast beds.Some stable operations are inefficient,and most of the operations are based on experience.There is an urgent need for the stable car to have the ability to detect the lateral resistance of the track bed online in real time to improve the quality and efficiency of the stable car’s operation.In view of the above problems,this thesis studies the lateral mechanical characteristics of ballasted track structures.The purpose is to provide theoretical support for the on-line real-time measurement of the lateral resistance of the track bed and the optimization of stable operation parameters.Field experiments on the lateral resistance of the rail platoon and the lateral resistance of the track bed were carried out,and the measured relationship between the lateral resistance of the platoon and the track bed was obtained.The statics model of the ballasted track was established by using finite element software,and the influence of the structural parameters of the ballasted track on the lateral resistance of the rail platoon was analyzed,and the theoretical quantitative relationship between the lateral resistance of the rail platoon and the lateral resistance of the track bed was obtained.The results show that it is feasible to indirectly measure the lateral resistance of the track bed by measuring the lateral resistance of the rail row,and it is feasible to predict and evaluate the lateral resistance of the track bed by measuring the lateral response parameters of the rail platoon on-line and real-time by the dynamic stability car.Through the analysis of the lateral vibration characteristics of the ballasted track structure,it is found that the natural frequency of each level of the ballasted track structure increases with the increase in the lateral resistance of the ballast bed,which corresponds to when the lateral resistance of the ballast bed is 2.4～16.8k N/sleeper.The first-order natural frequency of the ballasted track structure is 9～19Hz,and the maximum lateral vibration amplitude of the track occurs at the first-order natural frequency of the ballasted track structure,which has certain guiding significance for the selection of the stable operation parameters of the ballasted track.On the basis of the statics model of the ballasted track,the lateral dynamics model of the ballasted track structure is established.First,the dynamic response characteristics of the rail,sleeper and ballast bed under the typical operating parameters of the stabilizer are analyzed,and then the excitation frequency and vibration frequency of the stabilized operating device are analyzed.The influence of vertical downward pressure on the lateral vibration response of each component of the ballasted track.Finally,the influence of the structural parameters of the ballasted track on the lateral vibration response parameters of the rail row under the excitation of the stabilizer is analyzed.The dynamic analysis results show that:(1)The lateral vibration response curve of each track component under the excitation of the stable operation device is a relatively regular sincosine curve.The lateral vibration response of the rail and sleeper has good synchronization,while the lateral vibration response of the track bed is lagging.For rails and sleepers.(2)The lateral vibration response amplitude of the track bed is reduced by about 93% compared with that of the steel rail,and the effective excitation range of a single stabilizer is about 10 sleeper intervals.(3)The amplitude of the lateral velocity and acceleration response of each component of the track increases with the increase of the excitation frequency of the stable operation device,but the amplitude of the lateral displacement response first increases and then slowly decreases with the increase of the excitation frequency;The lateral dynamic response of components is almost unaffected by the vertical downward pressure of the stabilizing work device.(4)The lateral vibration response amplitude of the rail row at different excitation frequencies of the stable operation device varies with the lateral resistance of the track bed.The failure of a local sleeper will significantly affect the response amplitude of the lateral vibration of the rail row.The excitation frequency of the stable operation device is less than It is more obvious at 20 Hz.The research results in this paper lay a theoretical foundation for the prediction and evaluation of the lateral resistance of the ballasted bed by measuring the lateral response parameters of the rail row in real time during the operation of the power stabilized car,and provide theoretical support for the optimization of the stable operation parameters of the ballasted track,and for the construction of the ballasted track The formulation of norms and acceptance criteria provides a scientific basis.