Abstract: Based on a large number of test results and accumulated test experiences, some specific principles of scale of test gradation are summarized. The influence of gradation situations in coarse aggregate on its filling relation is investigated based on the variation of the content of , where is the aggregate with diameter ≤5 mm. It is shown that the more excellent the gradation is, the better the filling relation of the coarse aggregate is; and the coarse aggregate can reach a larger dry density; otherwise, the worse filling relation of the coarse aggregate makes it difficult obtain a larger dry density. Under low confining pressure, the influence of gradation situations on dynamic properties of rockfill is not obvious; and with the increase of the confining pressure, the dynamic properties of rockfill with good gradation obviously become satisfactory. Owing to its good roundness of particles, the influence of gradation situations of sandy gravel on its dynamic properties gradually decreases. According to the above rules, for high earth-rock dams, it is necessary to adopt coarse aggregate with good gradation as dam materials; and the advantage of mechanical properties of the coarse aggregate under high stress may be employed to control the integrated deformation of dams and to increase their aseismic performance.

Key words: gradation, coarse aggregate, dynamic property, influence factor, experimental study