Research purposes: High speed railway slab track poses high requirements on the durability and rigidity of subgrade. In order to guarantee the quality, both China and Germany set up corresponding quality control standards. These two standards have both connections and differentiations. For the study of the corresponding relationship between the Chinese and German indices of the quality control for the subgrade, foreign proven experience could be referred,as to perfect the subgrade quality control standards suitable for the Chinese situations as soon as possible.
Research methods: Firstly, this paper makes comparison and analysis theoretically on the indices of subgrade filling quality control standards, and points out the connections and differentiations between these two standards. Secondly, in connection with a case study of a subgrade filling on a passenger dedicated line, both Chinese and German standards are adopted respectively to carry out the related teats to set up the corresponding relationship between the Chinese and German indices under such testing conditions.
Research results : The compaction quality of medium and coarse-grained soil controlled by the unified porosity value in the Chinese standard is to be further investigated.
Research conclusions: For specific fills, corresponding compaction tests shall be made to determine the porosity value corresponding to compactness control indices; adoption of , could indirectly verify the reached compactness of the fills; good dependency relationship exists between and .