Dynamic Response Analysis Of Unsupported Sleeper In Twin-block Ballastless Track

In recent years, with a large number of domestic high-speed railway constructions, ballastless track has been widely used. As a major type, twin-block ballastless track has been laid on many high-speed railways and Passenger Dedicated Lines. In the use of twin-block ballastless track, a number of issues gradually arise. Among these issues, the poor adhesion between slab and prefabricated sleeper is more prominent. The phenomenon of unsupported sleeper in twin-block ballastless track has been found on the SuiYu railway.This thesis studied the phenomenon of unsupported sleeper in twin-block ballastless track, and mainly analyzed the effect on slab because of the unsupported sleeper, so as to provide a reference to maintenance of the track structure. Through appropriate assumptions, by using of the finite element method and the variational method, the author set up the dynamic equation which was based on the vehicle-track vertical vibration model, and also input the excitation of track, at last solved the equation by using of time-history dynamic analysis.By studying four kinds of conditions:single unsupported sleeper, two adjacent unsupported sleepers, two interval unsupported sleepers and three consecutive unsupported sleeper, this paper solved the vibration response of the track components under different cases, and get the additional force between sleeper and slab, then added it to sleeper force under normal condition, at last obtained maximum pressure values by each case. The author made the maximum pressure values above as static pressure on slab, set up static analysis model in ANSYS, solved stress distribution of slab beneath the sleeper, analyzed the damage of slab.Through the above analysis, the impact on slab concrete by unsupported sleeper can be received, so we can speculate the possible destruction of slab according to the allowable stress value of concrete, and make appropriate recommendations, provide a reference to maintenance for the track.