Re: Plumber laid asphalt is collapsing - should I be freaking out?
I agree with everything Jack just stated.
Depending on the depth that the trenching was done, you can expect up to 12" of compaction as the dirt settles and repacks over time. If the driveway was not properly packed - in layers - as the trench was filled, you're going to have the problem you face now, particularly if you've been driving a vehicle across the area.
The hole at the side of the house is likely more pronounced because no compaction was done under the structure, so even more settling will be experienced. Since the "fresh" dirt from the trench will move more freely than the undisturbed soil around it, it is no surprise that you've got a sink hole next to the house. Now, If a sink hole continues to form, even after repeated backfilling of a deep hole such as the image shows, then there is a problem with subterranean erosion, likely caused by the newly laid drain line.
At this point, try to stay on good terms with your plumber. The fact that he's willing to come back and address this recurrent problem seems as though he is trying to keep you happy. If the settling or erosion problem persists, then it might be time to escalate.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!