Experimental and numerical study on the influence of deterioration on the mechanical properties of graded gravel fillers during vibratory compaction

The research gap on the deterioration characteristics of graded gravel fillers during vibratory compaction has resulted in challenges in determining the optimal vibratory time for gravel fillers. In this paper, based on the self-developed compaction instrument, the critical vibratory time (Tlp) corresponding to the inflection point of compaction mechanical was proposed to characterize the deterioration state. Then, the deteriorated-induced evolution of gravel filler based on CT image are investigated. The CT test results show that when the vibratory time exceeds Tlp, the overall shape of the coarse particle remains unchanged, but their surface corners gradually undergo abrasion crushing. Next, a novel geometric modeling method is developed to simulate coarse particles with different abrasion levels by adjusting the parameter N, and as N increases, the abrasion levels of coarse particles increase. Finally, a series of compression tests are conducted with different abrasion levels of coarse particles via DEM to explore the mechanism of mechanical properties deterioration. The numerical results show that increasing N reduces both the peak strength and residual strength of the specimens, indicating decreased isotropy of contact and tangential contact force. The specimens with higher abrasion levels limit strong force chain formation, reducing the contribution of fine particles and increasing particle rotation. This study makes a significant contribution to the field of vibratory compaction quality control by providing a viable approach for a comprehensive investigation of vibratory compaction deterioration.