This paper based on the dynamic triaxial tests of completely decomposed granite samples of the Wuhan-Guangzhou passenger line to study the relation of the accumulated residual strain and the load times of completely decomposed granite and cement improved soil, and analyzes whether they meet the dynamic strength and cumulative cyclic deformation indicators and requirements of high-speed railway under vehicles load. High-speed driving when the subgrade generate residual plastic deformation. Residual plastic deformation of the continuous development will inevitably lead to the deterioration of the road, such as cracks, jack mud, uneven subsidence and long-term slow subsidence of the roadbed. Therefore, by studying the dynamic strength and the size of the dynamic stress of different parts of subgrade embankment to determine the appropriate filling parts of filler and control the final dynamic stress level of the roadbed at a reasonable range in order to ensure lines in good condition in the design life.
