| The foundation of unimpeded safe high-speed and heavy-haul railway is railway line engineering. The track structure will deteriorate continuously with complex climatic conditions, high frequency of train load cycle, complex infrastructure and geological conditions. Then it may lead to uncontrollable change of integral stiffness and stability of the railway, which has a seriously bad impact on normal service performance of the whole line. So it is really urgent to studying the overall railway and developing a detection and evaluation for the dynamic state of the line under the fast and large-scale building of Chinese railway.The most important link to carry out the whole structure study of some line is loading test. A series of tests based on TLV are beginning in China. Now the reasonable TLV key parameters of mobile loading and fixed-point loading is not clear, which seriously influences on the precision and reliability of the loading test result. Otherwise, the analysis method to identify result characteristics of the bad state of track structure after tests has not been established yet. Therefore, the important function in the inspection and maintenance work of new line and existing raiway is waste. It is particularly necessary to investigate the questions above for effective guiding the next application of TLV in China. The main research works are as follows:(1) Establishment of TLV-track-subgrade spatial coupling dynamic model and TLV fixed-point vibration model.For the theory lack of TLV simulation research, the"TLV-Slab Ballastless Track&Heavy-haul Ballast Track"spatial coupling dynamic model has been established reference for the existing technology of vehicle-track coupling collaborative simulation. Then the "Slab Ballastless Track&Heavy-haul Ballast Track"refinement vibration model is established with the finite element method. The model has solved the problem to apply the stable loading on track and load shedding on vehicle at the same time.(2) Providing the reasonable suggestion of key loading parameters about TLV.The dynamic characteristics of different track component have been analyzed by the dynamic theory in the process of loading based on the demand of field testing. The reasonable moving speed, loading force and the sensitive frequency of fixed-point loading are put forward when TLV is testing the track structure stiffness. It must pay more attention on these frequencies or avoid them in the actual test. (3) Research about the influence law on the dynamic characteristics of track structure by changing the track structure parameters under TLV mobile loading.The influence law on the dynamic characteristics of track structure is found out by changing the track structure parameters under the mobile loading based on the demand of practical application. It points that the sensitive degree on the dynamic characteristics of the changing of the parameter of track structure is different to the different track component under the mobile loading of TLV, which can be foundation for further application and field test of TLV.(4) Proposing the analysis method to identify the bad state of track structure by TLV.After studing the dynamic response when TlV is loading on the weakness area and follow the demand of TLV field test, the identification features on the bad state of track structure is proposed including subgrade settlement, fastener failure, mortar debonding, unsupported sleeper, cement hardening and nonstandard height of ballast when the TLV is loading. |
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