The repair works due to settlement issue for any building projects are usually repair in term of cosmetics/appearance. This is due to the underlying cause of settlement have not been identify/address or simply ignored during design or during construction. What we see or repair on site is the symptom due to settlement problems.
When we put extra load ie sand filling/suitable earth, we actually adding more load to it. Just imagine with the existing fill height, the settlement still occur thus when we put more load, it will settle more.
Settlement or consolidation is time dependent behaviour !
I would suggest that we settle the problem in much early during design stage. If we do after completion of project, we just address the symptom not the underlying problem.