We installed brick pavers on the approach to our house. After a few years, they started to sink by the doorway of the house. When we installed them, we did everything right, compacting down the sand, making it level. I did notice a snack hole on either side of the sidewalk, so I suspect that compromised our sidewalk. We also saw the snake, we named him Jake. In order to fix the sunken brick pavers,we needed additional sand and some rocks to support the pavers (and keep Jake from making another tunnel).
If you have the same problem with brick pavers, what we did may work for you as well.
sunken brick pavers project
Start by removing the existing the pavers and set them to the side. Try to keep them in order, so they will go back into place easily. If you don’t it will be a frustrating puzzle to put back together.
Inspect the area to see what has caused the pavers to sink. Has water washed away the sand, critters gotten into the area or something else.
You will need to rebuild up the area that has been compromised.
We added small rocks down at the bottom, to help build up the area, give some stability and keep the snake from burrowing another hole under the pavers. You then need to compact your sand down and ensure it is level.
Once the sand is compacted, you can start the puzzle part of the project. Put the pavers back down. You may need to get a rubber mallet to coax them into the position.
Once they are in, you can add sand on top of the pavers and brush it in to help lock them in place (if you want).