Exploring the effects of gravel shapes on vibration compaction behaviours of coarse-grained mixtures via DEM simulations

ABSTRACT

Coarse-grained mixtures composed of coarse gravels and fine sands are widely used in subgrade constructions, coarse gravels of which contain rubbles and pebbles with different roundness (R_d). To investigate the effect of gravel shapes on the compaction behaviours of subgrades, the real-shaped gravel particles with varying R_d (0.2–0.5) were selected to establish coarse-grained mixtures models via the discrete element method (DEM). The contact parameters in DEM models were determined through a series of calibration tests, and the reliability of models was verified by vibration compaction tests with rubble-grained and pebble-grained mixtures. The evolutions of porosity, particle motion, and contact relationship affected by R_d were revealed from the macro-and mesoscales, and the influence of R_d on the stability of skeleton structures is discussed. As R_d decreases, the contact number tends to increase and the distribution of strong contacts is more uniform, the skeleton structure in which can effectively inhibit the motion of fine particles and the sliding between coarse particles. Conversely, the increase in R_d will cause the concentration of strong contacts, which further results in the sliding damage of skeleton structures and the improvement of compaction deformation.

KEYWORDS:

• Coarse-grained mixture
• vibration load
• compaction deformation
• discrete element method (DEM)
• particle shape

Acknowledgment

The authors would like to express their appreciation for the financial assistance.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by the Fundamental Research Funds for the Central Universities of Central South University: [Grant Number 2021zzts0247] and the Key Technological Innovation Project of China State Construction Engineering Corporation: [Grant Number CSCEC-2021-S-2].