Probability Predicting Model Of Ballasted Track

Track is a kind of random and discrete engineering structure in mechanics. With speeding up, train loading causes track to deform. Thus predicting track deformation could help railway maintenance sector plan and lay a theoretical basis for strengthening track structure.The aim of the paper is to predict track deformation considering some random factors from mechanics. Firstly, the paper sums up international track settlement theories and builds up a FEM model to work out deformation including parameters mounting, unit selection, length of the model, loading mode and so on.Secondly, the paper comes up with 18 kinds of load conditions, track parameters and vehicle parameters, works out 18 kinds of wheel load by the wheel-rail model and the distribution of wheel load, validates whether wheel load complies with normal distribution by Kolmogorov-Smirnove Test and calculates some statistics such as skew, kurtosis and so on for analyzing the distribution character of wheel load and studying how track conditions and velocity to affect on the distribution character of wheel load.Thirdly, the paper studies the relationship between track irregularity amplitude, wheel load and the vertical acceleration of car body, the relationship between track irregularity wave length and the vertical acceleration of car body with the data of instrumented wheelset on Hukun Railway and Jinwen Railway from time, frequency and validates whether wheel load in field complies with normal distribution by Kolmogorov-Smirnove Test.Fourthly, the paper comes up with main factors affecting deformation, namely number and amplitude of wheel load, density of track bed and track stiffness based on international studies. The paper studies the relationship between track bed modulus and loading number, that between track bed density and modulus, that between track bed stress and deformation and that between track deformation and track stiffness. Then the paper works out plastic accumulative deformation of track bed along the railway under different load distribution by the former FEM model. And the paper studies whether track deformation complies with normal distribution by Kolmogorov-Smirnove Test, predicts track irregularity distribution before and after certain transportation volume and works out the predicting function between transportation volume and track deformation.Fifthly, the paper studies how track state and vehicle velocity to affect on statistic character of track deformation and track irregularity through calculating statistics and correlatives of load to deformation. Then the paper tests the stability of track irregularity using Wheel Numbers Method and works out mileage-frequency PSD of track irregularity, track irregularity PSD and its fitting curve under 18 kinds of wheel load under certain transportation volume. And also the paper validates predicting results of track irregularity using the former predicting function by track irregularity PSD after 5 million tons of transportation volume on Jinghu Railway Down Line from time and frequency.Finally, the paper makes a conclusion and a prospect for further work through the former discussion.