Abstract: There are about 4 methods, i.e. scalping method, equivalent substitution method, similar gradation method and hybrid method, to model the site gradation of soil materials according to the code. And 15 modeling gradations of coarse-grained materials from an engineering site have been modeled by using these gradation scale methods; by the same token, their equivalent particle diameters are 60, 40, 20 mm. The maximum dry density tests also have been conducted to these modeling gradations in the same vibration energy; and the distributing law of maximum dry density value can be concluded. In conclusion, the maximum dry density value goes together with the nonuniform coefficient, curvature coefficient, maximum particle diameter and lower groups (≤5 mm), etc. And a corrected gradation parameter has been put forward to normalize the relationship between maximum dry density and relative parameters of gradation. To justify the rationality of normalized formula, the site coarse-grained materials compaction tests have been conducted with the sample diameter of 1 m.

Key words: scale effect, gradation scale method, coarse-grained soil, maximum dry density, gradation parameter