I'd never heard of this before, then I caught a show called Zombie House Flippers - zombie houses, not the flippers, themselves ;-p - where one of the homes had a pool where they were worried about this very thing. They had to empty it to repair it, and it had been raining a lot, so they wanted the repairs and refill done as quickly as possible. They were somewhere in the southern part of Florida.
This is not uncommon in Fl. If the pool is empty and we get alot of rain consistently,the ground water can actually force the pool out of the ground.
Theres a small hotel in my town
that filled in thier pool with concrete and turned it into a basketball court
I have a fallout shelter under my back yard, and if I do not keep it full of water it rises a little, and now there is a rectangular outline on my lawn.
Look up ferro cement boats