Wanna make the easy above ground pool 5 feet deep instead of 48 inches

[DIYdon]

I Wanna make the easy above ground pool 5 feet deep instead of 48 inches. I plan to buy a 15 foot diameter 48 inch deep - one of those that has no metal frame, just an air ring that floats the sides up. I doubt the flooring it is stretchy enough to, but I was thinking maybe it is and I could dig a foot lower in the center. Maybe I could cheat in a bit of a sin wave to help stability - that is to make the ground under the perimeter a little deeper than the ground under the 7 foot diameter portion. So at the 7.5 foot diameter, go down a foot in the ground for the whole 6.283185307d circumference (or 2pir or 2pi times 7.5 foot circumference), and at the 7 foot diameter go down a half foot for the circumference of its circle, then gradually slope rise over run from there at 2/6 so it is 5 feet deep in the center. Think? If not, what about patching a piece of an old pool floor in the center? What do ya'll think?