Abstract: In order to systematically study the densification mechanism of landslide dam material during rolling dynamic compaction, based on the self-designed model device for rolling dynamic compaction and particle image velocimetry technology, the effects of different construction parameters on the deformation and particle displacement of the landslide dam material foundation were studied. The test results showed that the rolling dynamic compaction process is a combination of impact and rolling. Due to the horizontal impact, the deformation of the foundation under the impact point is asymmetric. The combination of "high speed and low-weight roller" construction parameters would improve the impact effect, and weaken the compaction effect, resulting in poor surface smoothness of the foundation. The maximum displacement during the reinforcement occurred when the arc surface of the triangular impact wheel was in contact with the soil. Afterwards, due to the rise of the center of the impact wheel, the foundation appeared partially elastical rebound. The increase of roller speed promotes the impact energy transfer to the deeper depth, but the improvement width is limited. The increase of roller weight promotes energy transfer to both horizontal sides, but the improvement depth is limited. For the Yigong landslide dam material foundation in the model test, the optimal towing speed for the rolling dynamic compaction is about 0.75 m/s. The results could provide a theoretical basis for the reinforcement of impact rolling of the shallow layer of landslide dam foundation.

Key words: landslide dam material, rolling dynamic compaction, meso-mechanism, particle motion, displacement