振动荷载下级配碎石颗粒运动及其能量特征试验研究

Unbound aggregate materials (UAM) featuring large air voids are increasingly used to construct pavement base/subbase layers for the initiative of sponge cities due to their desired drainage performance. However, particle motion and spatial distribution of kinetic energy during particle rearrangement process induced by vibratory loading are still not clear. This paper presents the results from laboratory vibratory plate compaction tests conducted on UAM specimens under different combinations of vibratory parameters with different levels of Gravel to Sand ratio (G/ S), which is proposed previously from particle packing theory. The innovative SmartRock (SR) sensors were placed at different positions inside the specimen to monitor the real-time particle motion, whereas kinematic energy and its spatial distribution were analyzed from the acceleration time-history signals collected by SR sensors. To assess the compaction quality, a new index was proposed based on particle motion and kinematic energy. The results show that the vibratory compaction can be categorized into two distinct stages. In the first stage, the majority of the energy is dissipated by coarse particles moving mainly vertically and the compression of air voids, and the dense skeleton structure is not formed. In the second stage, coarse particles mainly translate in the horizontal plane and rotate in the vertical plane, and gradually tend to lie flat with long axes oriented horizontally, while the majority of the energy is dissipated for filling air voids, thus leading to the occurrence of densely packed skeleton structure. The particle movement and kinematic energy indices in the middle of the specimen can be used to assess the compaction stage and quality. The particle motion in the lateral direction transitions from continuously ascending to gradually descending to almost no kinematic energy, indicating that the specimen was compacted to a relatively dense state. The research results can provide reference for intelligent assessment and control of continuous compaction quality of UAMs.