Experiment Analysing on Portrait Dynamics Performance of Transition Subgrade between Bridge and Tunnels on Ballastless Track

Building high-speed railway in mountainous areas faces problems in handling differences between short transition subgrade of bridge and tunnels. These lead to serious differences on variation and rigidity flexure on that stretch of railway, which threat to safety of the train and comfortableness of passengers when the train goes through. The problem comes clearer in building subgrade for high-speed railway at transition stretch linking bridge and tunnels. One existing solution for the issue is to design rigidity variation. The report on general experiment results on performance of portrait dynamics of transition subgrade between bridge and tunnels on the Sui-Yu ballastless track railway route shows that: 1) Axle loading capacity of main automobiles is light, carriages' capability of shaking reduction is good. These factors cause only light seismic shaking on edge of subgrade of transition stretch linking bridge and tunnels, and do not show clear effect of seismic shaking to the whole route. However, C80 truck car made double moving variation effect to the route in comparison with effect caused by movement of CHR2 main carriage. 2) Loading capacity and speed of main carriage has caused small-scale effect to moving variation, speed and acceleration of the route. The rule of moving variation, speed, and acceleration of subgrade on transition stretch linking bridge and tunnels has changed unstably. The reality shows that rigidity variation solution applied for subgrade construction on transition stretch linking bridge and tunnels satisfies design demand.