What Causes Concrete to Sink into the Soil? 

It essentially has to do with the concrete’s weight. If the soil is harmed in any way, it will most likely be unable to sustain the weight of your pool deck, as well as additional structures such as a concrete patio or slab. Pool decks also tend to bear additional weight from people, furniture, screens, and the water in the pool. All of these causes might lead to cracked and uneven areas of your pool deck, especially if the soil underlying it has difficulties.