This was a reinforcement constructions done on Dongsongjeong station that was settled due to matt basic construction on the weak ground. The most certain solution in dealing with a weak ground is to drive in a stake through the hard ground and building a building on top of that. This station previously reinforced by adding cement on the hole that was drilled on the outside of the building through the ground once the building started to tilt. However, the building continued to tilt 1mm every week. The problem was fixed by indenting steel stake inside the building.
Cement grouting residue
Cracks on the building due to tilting
Reinforced stake indentation