Pool deck separated from pool coping

[I3igDmsu]

Hi everyone. I'm a new pool owner and purchased a house with an in-ground pool with some issues with the concrete deck shifting away from pool. The concrete slabs have shifted away from the pool due to erosion over time. In some places, there is near a 6" or less gap from the pool coping to the deck (see picture). Does anyone know of a technique to push these slabs back up toward the pool or how to fix this? Would it be feasible to fill these with Quikcrete, leaving a 1" gap between the coping and Quikcrete for expansion and fill with a foam rod and self-leveling caulk?
Thanks for the help!

Picture: http://st.houzz.com/simgs/1e323cae0542d67b_8-3643/home-design.jpg