1) I couldn't quite hear him, but I think he meant Seoul Ring Expressway, and it was an overhead one if you were wondering.
2) The cables are threaded to make a sling.
3) He's talking about bringing back an extremely rare piece of Korean history (that had almost been obliterated).
4) Adding to the millions of displaced persons...
5) Crack and pulverise concrete and shear steel.
6) The silt they removed...
7) There is such a thing as a water table which is what I believe the Korean man was referring to. It was upstream of the river, the name of which was said (I think).
8) Nothing can diminish the euphoria. It may have been confusing because of the narrator's use of /ɒ/ instead of /ɔ/.
[Not a teacher]
Student or Learner