I agree with Reno. This is not a code issue, but a design issue. Receptacles are permitted faceup in/on the floor. The subject to severe physical damage is important. The only one(s) who can make that judgement are the ones who can actually physically see it. From our vantage point here, we cannot.
They make "doghouse" type enclosures designed for this type of installation. Would that be a consideration? Remember part of the design consideration is the environment in which this installation is in...CHILDREN!!!
