Study On The Influence Of Frequency And Amplitude On Tamping Effect

With the development of ballast railways towards high-speed and heavy-loading,the maintenance of railway lines is also increasing.Tamping operation is one of the important methods for the maintenance of ballast railways.Choosing appropriate tamping parameters can effectively improve the mechanical properties of the track bed.At present,most scholars at home and abroad have carried out research work on tamping operations in common ballast beds.,and there are relatively few problems in the research on tamping operations of high-speed ballast bed.To this end,this paper conducts a comparative study on the tamping operation of common ballast beds and high-speed ballast beds,comprehensively explores the best tamping parameters of the two types of ballast bed tamping operations.The main research contents and results are as follows:First,use the image recognition method to establish the discrete element model of ballast particles,and on this basis,establish the three-dimensional discrete element model of common ballast bed and high-speed ballast bed tamping operation;next,the vertical stiffness and lateral resistance of the ballast bed are selected,combined with numerical simulation and physical experiment,to verify the validity of the tamping operation model of common ballast bed and high-speed ballast bed,which shows that the numerical model is reliable;then,in the numerical simulation of the tamping operation of the ballast bed,the uniform design method is adopted to design the numerical simulation scheme,and the law of the density and lateral resistance of the ballast bed is analyzed from the numerical simulation results;finally,using the frequency and amplitude of the tamping picks in the tamping operation as variables,and the density and lateral resistance of the ballast bed as evaluation indicators,two regression equations for the respective density and lateral resistance of the ballast bed are constructed,and weighted the combination method optimizes the regression equations of the density and lateral resistance of the ballast bed with multiple objective functions,and determines the optimal tamping frequency and amplitude of the common ballast bed and the high-speed ballast bed.Through simulation analysis,it is found that under the same tamping parameters,the density and lateral resistance of the common ballast bed after the tamping operation are generally lower than that of the high-speed ballast bed.The overall change trend of the ballast bed density is to first rise rapidly,then reach the maximum,then fluctuate within the maximum range,and finally decrease.With the lateral movement of the sleeper,the trend of the lateral resistance of the ballast bed increases first and then stabilizes.For different ballast beds,the selected tamping parameters are also different.The vibration frequency of the tamping pick when the common ballast bed is tamping is 42.5Hz and the amplitude is 9.8mm,the stability of the ballast bed is better;When the high-speed ballast bed is in the tamping operation,the vibration frequency of the ram is 52.3Hz and the amplitude is 5.9mm,the stability of the ballast bed is better.The research process of this article and the relevant conclusions drawn can provide a certain reference for the selection of tamping parameters in ballast bed tamping operations.