Raising a concrete floating slab in my ground floor Apt
I have a ground floor apartment that has a floating slab concrete floor that is beginning to settle as much as 3 inches in some areas. The interior partition walls are not tied in to the structure frame but are setting on the slab floor. Some areas under the floor have settled as much as 36 inches due to prior excavation and not properly backfilling the excavation area. There is plumbing under the concrete, water & drain pipes. Is there a method where a loose aggregate could be pumped in through a hole in the slab that would surround the plumbing but not damage the plumbing structurally and then a pressure grout of some kind used to raise the floor to its original level?