Abstract: In this paper, the dynamic characteristics of the coarse-grained backfills of high-speed railway subgrade under the influence of traffic load are studied by the GDS dynamic and static triaxial apparatus. The results show that: when the cyclic stress is large, the greater the frequency of loading is, the greater the volume strain of coarse-grained subgrade backfill will be. The subgrade backfill will have higher degree of compaction. However, when the cyclic stress is equal to the confining pressure, the effect of the loading frequency on the cumulative volume strain of the coarse-grained subgrade backfill is limited; When the applied cyclic stress is large, the increase of load frequency leads to the increase of the resilient modulus of subgrade backfill, and the axial cumulative deformation of the coarse-grained backfill increases significantly; When the cyclic stress is close to the confining pressure, the load frequency has little effect on the axial cumulative deformation of the coarse-grained packing. According to the research results, the corresponding control measures for subgrade filling construction are proposed, which can provide reference for similar projects.

Key words: Traffic Load, High-Speed Railway, Subgrade Backfills