Abstract：The dam of Yixing pumped-storage hydroplant is a slab rockfill dam. The laboratory tests were made on the relation among gradation，density and content of mudstone and the physical and mechanical properties of rockfill material. The testing results show that the maximum dry density of rockfill should be tested by the platform vibrator. The compact rockfill materials are of the properties of high permeability，low compression，low failure strain and high shear strength. The graded material could be used as rockfill material. The relationships between the mechanical characteristics and mudstone content are statistically analyzed according to the testing results.
