Analysis On The Characteristic Identification And Evolution Law Of High-Speed Railway Track Spectrum

Track irregularity power spectral density as one of the indicators characterizes and evaluates macroscopic geometric state on a certain type of line,which is an important means of guiding track maintenance and repair,and an important input to design and evaluate dynamic performance of rolling stock,track,Bridges and other infrastructures.Therefore,it has theoretical and practical significance to in-depth research the track spectrum.Due to the high speed and high stability requirements,the high-speed railway requires many bridges and tunnels,such as the proportion of bridges and tunnels reached 78.6%on Chengdu-Guizhou railway.Yet it has little in exploring the relationship between the information track spectrum contained and the infrastructures,and as the growth of the high-speed railway operation time,the wavelength of the track spectrum composition and spectral density values also produce changes.Therefore,it has very important significance to explore the relationship between the characteristic wavelength and the structure under the track,the relationship between the evolution of track spectrum and seasonal factor and large machine grinding.To explore the relationship between the characteristic wavelength of the track spectrum and the structure under the track,this article presents a method for the identification of the spectral characteristics of different basic structures based on the periodic chart method.Based on track inspection data of the ballasted track and ballastless track which is the typical track structure in our country,the author identifies the characteristics wavelength of track spectrum on the different infrastructures?bridge,roadbed,tunnel?,different irregularity index?vertical,level,direction,gauge?.In addition,explores the causes of characteristics wavelength,verifies the correctness of the conclusion using the numerical simulation method.The main conclusions are as follows:?1?The characteristic wavelength of track spectrum is closely related to the infrastructure on vertical and level irregularity,which are influenced by the track periodic irregularities of the bridge and the roadbed,mainly distributed in the simply supported girder bridge plate?32.6 m?,the subgrade base plate?25m or 20m?and The¹₉)double frequency values.?2?The characteristic wavelength of track spectrum is also affected by the track periodic structure on vertical and level irregularity,but it is the secondary period that is superimposed with the main period caused by the periodic infrastructure.Such as bridge laying ballastless track,its characteristic wavelength will be ballastless track plate long?4.962 m and 3.685 m?for the minor period and increase the spectral density values of characteristics wavelength?4.68 m and 5.45 m?on the primary period.?3?The characteristic wavelength of track spectrum are basically irrelevant to the infrastructure on direction and gauge irregularity,but are related to the track structure?ballasts or ballastless?.To explore the relationship between the evolvement of the track spectrum and seasonal factor,this article is based on the three-year track inspection data of a long 300km line and local temperature distribution.The correlation analysis shows that the characteristic wavelength evolution of track spectrum was associated with time on vertical and level irregularity.In addition,it is negatively correlated with temperature on vertical irregularity,namely,the temperature is lower,the greater the spectral density value.Therefore,the author recommends maintenance department should pay more attention to transfinite problem of the vertical track spectrum in winter.However,the direction and gauge track spectrum change randomly with time.To explore the relationship between the evolvement of the track spectrum and large machine grinding,The article put forward the evaluation index of grinding effect:the mean square value rate r,also based on the three-year track inspection data of a long 300km line and maintenance information.Through calculating the mean square value rate at about-10%on vertical,level irregularity and vertical acceleration,the rate is about 2%on direction and gauge irregularity,lateral acceleration exists randomness,some at around-8%,others around2%.Namely,The track spectrum mean square value below 5 m has a certain degree decrease on vertical?level irregularity?vertical acceleration and lateral acceleration on part of the date through big machine grinding operation,but has no effect on direction and gauge irregularity.