PROBLEM TO BE SOLVED: To make the dismantling of track bed ballast easier by performing the stabilizer filling process separated into a spot-sticking filling process for combining the ballast together leaving the ballast gaps and a full filling process for completely filling the ballast gaps.
SOLUTION: Leak stop layers 8, 8 are formed by spraying to the side surfaces of track bed ballast to be stabilized. Next, a stabilizer is filled, and a spot- sticking filling layer 14 connecting the ballast together at its contact portions and adjacent portions is formed. Next, a stabilizer 9c is filled by using filling devices 11, 13. Since the ballast gaps have been already become smaller by the spot-sticking filling process, the stabilizer 9c will flow down while fully filling the remaining ballast gaps, stop after a flow-down to a certain degree, and this portion becomes a boundary between a completely filled layer 15 and a spot-sticking filling layer 14. Thus, the ballast lower portion is in a spot- sticking state among the ballasts, so that the lower portion of the ballast can be ruptured with a relatively less effort during maintenance work such as the correction of deviated track or the replacement of the track bed.