This was originally design as a massive space warp machine for large ships and such. The structure is colossal in size and so heavy that it needs massive support structure. Since it is massive and it's a space warp machine, it will need tremendous amount of energy to run. Also it needs to sits really high so ship can warp in/out without hitting anything. So the IMC carve out mountains, built the machine on top of it, and channel straight down to the planets' core to get energy to run this baby. (at lease that's the story I made up when designing this structure.)
Then the story change and this giant machine turn into Fold Weapon (planetary annihilation weapon).