Heave is the weight needed to counter the rising (uplift) of a swimming pool – regardless of how it is built. There are two sources of uplift; Hydrostatic, uplift pressure from water in the ground and ‘heave due to removal of overburden pressure’ – when soil is no longer compressed by the weight of the soil above (because it’s been removed to dig your swimming pool).
Once you know the pressure (uplift) you need to ensure the weight of the intended construction method will be able to resist any uplift – when the swimming pool is full of water and when it is empty to be cleaned.