My family started to build this area for our sulcata tortoise (11" in length shell). We are now questioning whether these are safe to use in the off chance "Wilson" tries to dig under and a brick would fall on him. Is this a valid concern?
@Tom uses them, however, he has a lot bigger area for the torts. With a smaller area like yours, it might be a concern. Maybe bury one brink level down. See what Tom says, he has lots of experience with blocks and sulcatas
I've been keeping sulcatas behind blocks since the early 90's. I've never had one try to dig out. They don't dig down and then back up. They just dig a burrow with one single tunnel down at about a 40 degree angle. They come and go from that one hole. A large adult that was not raised in these blocks can push them over if they really try, but they usually don't try. When they are raised behind them, they just don't try. Well, mine never have…
For an 11" sulcata, that I am sure is growing fast, you need to go another couple of blocks higher and much bigger. It will also be much more stable if you incorporate half blocks at the start of every other row, so the blocks are staggered. It gives the wall much more stability.