Abstract: Comparative tests on the density, mechanical and seepage properties of rockfill materials are performed by preparing the same in-situ grading curve as different grading curves based on the scale methods. The test results show that according to the scale by means of the equivalent replacement method, owing to that the content of soil particles less than 5 mm does not change and the filling relation between coarse and fine particles is poor, the corresponding density and mechanical properties are the worst, and the coefficient of permeability is the largest. According to the similar grading method, one of the hybrid methods, the content of soil particles less than 5 mm gradually increases and the filling relation between coarse and fine particles is obviously improved; the relevant density and mechanical properties become larger and larger, however, the coefficient of permeability gradually decreases. At present, there are no specific and definite stipulations for the grading scale methods in Chinese codes and specifications. It is necessary to propose scientific laboratory scale methods for rockfill materials based on large quantity of laboratory and in-situ tests.

Key words: rockfill material, grading scale method, laboratory test, effect