No The Ballasted Track Roadbed Dynamic Response Characteristics And Indoor Model Loaded Studies

As the construction of high-speed railway has accelerated, there is more and more ballastless railway built on soil subgrade. The vibration and deformation characteristics of subgrade, under high speed train load, need urgently to be researched in-depth. The influence of different factors on dynamic response of high-speed railway subgrade is analyzed by numerical simulation, and the loading program for the high-speed railway subgrade indoor model experiment was designed, which can simulate train load of different speed.The main work and corresponding conclusions is as below:(1) Through routine indoor geotechnical tests, the physical and mechanical properties of the filling were got. At the same time, many in-situ tests have been conducted during the filling of indoor subgrade model, and the calculation parameters in numerical simulation model were obtained.(2) The numerical simulation model was set up, in which the track type is CRTSⅡ, and the four couples of wheel loads of adjacent bogies of adjacent carriages is imitated by moving concentrated loads. After the comparison of modeling methods of full model and half model, the full model was employed.(3) In track type CRTSⅡ, the curves between time and reaction force of fasteners under different train speeds and different axle loads was obtained.(4) The influence of different track types and different axle loads on dynamic response of subgrade was analyzed. The results show that different track types have no apparent effects on dynamic stresses and displacements in subgrade, and amplitudes of dynamic stresses and displacements under different axle loads increase linearly.(5) The numerical simulation model of high-speed railway subgrade indoor experiment was set up. The rationality of indoor experiment model was proved by the comparison between former and latter simulation models. Aim at the indoor experiment model, dynamic responses of three loading programs, including loading by distribution beams, loading by short rails and loading directly on orbital plate, were analyzed. The comparison between them and the true state of train shows that loading by short rails is the best.