THe same thing happened to me last Sunday!!!!!!!
the liner just popped off and water gushed out. washing away sand from the perimeter and sending water down the street. I managed to save the last couple of inches just to try to save the liner - We suspect the problem was caused by a shifting caused by some water over the winter and spring getting under one side of the pool and washing away some of the sand. (we just put the pool up last July - first time pool owners). We have redone the perimeter of the pool with cement filler stuff instead of just sand -and built a ditch to redirect water from that side of the pool to eliminate the problem from happening again. After much agonizing, I also decided to scrap the beaded liner and am going to replace with an overlap. Don't know if that will be safer or not. IN any case, I FEEL YOUR PAIN!!!!