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.