These drain collars all had different grades resulting in asphalt like a roller coaster. We demolished a 10' x 20' x 6" area and tossed in a 5/8" bi-directional grid of steel every 3'. Reset the grade on the collars and poured a reinforced slab.
Turn out:
Start:
Click this link to see more photos:
https://drive.google.com/drive/folders/1DAAL0AhpbEHPL1ZDBCwqTNiQ3N3Dg5dM?usp=sharing