Rising pool

[PeterR]

Three years ago our plastic liner was replaced by an applied fiberglass coating on the advice of our pool specialist. It was poorly done and leaked badly, allowing a lot of water to escape to below the pool. We had that replaced by a new plastic liner. However, since the leaks happened our pool (8m x 4m) has been rising above the surrounding tiling by about 2cm a year, so there is now a big gap, and the tiles are also beginning to get lifted up in places. I am worried about the damage that this movement may be doing. Has anyone else had this problem, and is there a fix for it?

Currently, water can run down the gap between the tiling and the pool edging, so I suppose for a start I ought to put in a watertight joint to prevent the entry of further water (I tried this last year but subsequent movement has broken it up).

[czechmate]

Completely filled pool CAN NOT rise out of the ground. Even if it was made of very thin fiberglass. (You have displacement weight plus friction of the embedded object).
I assume that yours is a gunite. It would deny laws of physics-Archimedes law in particular.
Please state more in detail, what type of pool you have and what tiles you talking about.
Is it pool deck tiles? Pool deck shoud be tied to pool beam with dollies (steel rebars) at least every 3 feet to ensure better structural integrity of the cool deck. I did mine every 24 inches.

[PeterR]

Well, the pool definitely IS rising. It's set in a tiled terrace, the tiles being laid on concrete. The pool itself has a plastic liner. I think the pool is contained in a galvanized steel box.
I have had our builder look at it, and he says the ground under the pool is expanding due to the amount of water it has absorbed. We don't know what sort of material the pool is resting on.

[czechmate]

It is very unlikely, that water table below the pool can develop a pressure higher than 57 metric tons in order to raise it.
That is the about the weight of your pool if only 6 feet deep and without considering the friction of pool sides.
I would suspect that the "terrace" you have mentioned has something to do with your current structural problem.

[allclearpools]

It is very unlikely, that water table below the pool can develop a pressure higher than 57 metric tons in order to raise it.
That is the about the weight of your pool if only 6 feet deep and without considering the friction of pool sides.
I would suspect that the "terrace" you have mentioned has something to do with your current structural problem.

Depending on what type of soil they have it VERY possible. Here in Dallas there are multiple account of pools full of water becoming out of level by as much as 6". Heavy rains can cause this problem.