Figure 4.
Process of DEM ballast model establishment: (a) ballast particles distributed in the box; (b) initial stacking equilibrium state of the ballast particles; (c) ballast particles assembled in the ballast box; (d) form the ballast bed.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.