Water coming in below sump pit corrugated pipe! Is this normal?
Your house is probably surrounded by a drain pipe laid on a bed of gravel to allow water to flow from the ground into the pipe. Gravity drains this pipe to the lowest point, your sump pit. The pit is also filled with gravel to let water perc in from the ground so it can be pumped out and away from the structure.  As long as your pump is able to keep up with the water coming into the pit it sounds like it's working as designed.