Evaluating ballast stabilization during initial compaction phase

The railroad ballast initial compaction phase occurs immediately after the construction or maintenance of a track is finished. The ballast particles are densified into a more compact state after certain load repetitions. With increases in heavy haul trains, the heavy loads imposed on the track significantly change the ballast behavior. In order to investigate the ballast particle movement in different track conditions, this paper presents a series of ballast box tests. Three types of tests were conducted as follows: one with an unstabilized track section, one with a track section geogrid-stabilized at a depth of 30 cm, and another one with a track section geogrid-stabilized at a depth of 40 cm. The track section consists of two half-crossties, a rail, ballast, subballast, and subgrade. Four wireless devices, "SmartRocks, " were installed underneath the rail seat and underneath the shoulder at a depth of 30 cm and 40 cm, respectively, to monitor the ballast particle movement under cyclic loading. The ballast behavior in different sections is compared and discussed in this paper.