Abstract: Based on dynamic testing technology applying (earth pressure cells, EPCs) and (linear variable differential transformers, LVDTs), combining with the field vibration compaction tests, the internal stress and deformation characteristics and energy input mechanism of rockfill were studied. In the process of compaction, the maximum dry density of rockfill was determined. The results showed that: 1) The additional peak stress of rockfill in the depth range was between 0.3?1.4 MPa. The dynamic peak stress was between 0.22?0.82 MPa, which decayed exponentially along with the increasing of the depth of rockfill. 2) The measured dynamic strain significantly lagged behind the dynamic stress. With the increase of rolling times, the hysteretic cycle became steeper and smaller, while the soil stiffness increased and the damping decreased. 3) Dynamic stress, static stress and deformation were obtained through spectrum analysis and filtering methods, based on which the relationship between the input energy of the vibratory roller and the measured dry density was established. Then, the maximum dry density of rockfill and its relative density under different rolling times were calculated. This method can provide a basis for quality control of rockfill dam using the relative density index.

Key words: rockfill dam, vibration compaction, stress and deformation, filtering, relative density