Saturated soil at the edge of an excavation may cause a collapse that is dangerous and will require costly repairs.
The goal is to keep the soil relatively dry using a series of tarps around the perimeter. The tarps should be zip-tied to the bond beam steel and they should extend beyond the perimeter of the excavation by at least 10-feet (3 meters).
Rain that hits the tarp should sheet away from the pool and should not puddle even 10-feet from the edge. This may require that the inside edge of the tarps be elevated using wood strapped to the wall steel. The image below shows only one tarp but you can imagine the entire perimeter protected this way.
Water that enters the excavation itself should be captured by a bed of gravel and pumped out of the deepest point with a submersible pump (see article here).