How to handle unqualified compaction of earthwork backfill?

When earthwork backfill compaction is unqualified, you can't just let the roller run a few more times and call it a day. Many on-site problems stem from moisture content, layer thickness, and the material itself. If the soil is too wet, it becomes 'spongy' the more you roll it; if it's too dry, it looks hard on the surface but remains loose underneath. I once did a section of trench backfilling…