Analysis of the Subgrade Dynamic Stress Under the Trains Opposite Running on Double-track High-speed Railway

The dynamic finite element coupled model of train-track-subgrade system was established for two CRH3trains opposite running on the double-track high-speed railway via ABAQUS to analyze the dynamic stress distribution and transfer rule of this system's subgrade under the moving units with different coupling speeds.Resultsindicate that,dynamic stress distributed along the lateral direction in surface layer and bottom layer of subgrade bed is unsymmetric,but in embankment is symmetric relatively. The dynamic stress attenuates almost linearly when the depth is less than 2.7 m away from the surface of the surface layer of subgrade bed,the value of dynamic stress accounted for about 50% of the maximum stress. The dynamic stress attenuates slowly within 2.7~7.2 m and slowest beyond 7.2 m. The equivalent stress amplitude is lower with the increased of the opposite running units speed beyond 4.5 m depth. The stress distribution of the surface layer of subgrade bed presents to be a double-hump,and the stress reaches its maximum value when the first and second bogie is lateral coaxial respectively. With the speed of opposite running units increasing,the dynamic stress's vibration amplitude also increases,with more durable and harmful influence on the surface layer of subgrade bed.