Floor outlets in earthen floor?

We are putting an earthen floor in an addition that we have built onto our home (original structure is a 1960's brick rancher that we are changing quite drastically). It's approx a 20'x20' room that will be the family/living room for our 6 person household. We'd like to put a couple of floor outlets in the middle of the room so that we can plug in lamps, etc, to avoid having cords that our little ones and aging parents will certainly find hazardous. Anyone have any experience with or knowledge of what materials we can use to allow the electrical work to be safely housed under the earthen floor? Thanks in advance.

Janet,  you can buy a grey pvc floor box from Home Depot or lowes.  The box is round and has several ports to receive pvc conduit.  I use these when we pour concrete floors, so should not be a problem with earthen floors.  Just make
Sure to set the box so the top edge is even or just proud of the finished floor height, and trim later if required.  The box comes with an insert that gets an outlet attached and the insert is glued into the floor box.  Run the conduit up into a wall and terminate in an outlet box, don't bury the box in the wall.  Note that most jurisdictions won't let you run Romex in conduit, so buy the required length of thhn in black, white, and green, of appropriate size and install in the conduit.  When it's time to install the outlet, I like to assemble the outlet in the brass floor plate, swab on the pvc glue (I use the glue for pvc water lines, the grey conduit glue sucks) on and line up the outlet however it should orient and press into the floor box for a perfect fit.  Don't glue in the outlet receiver too soon or it ends up getting stepped on or debris ground in it, or scaffolding wheels jammed into it.  

Thanks, Kevin. We weren't sure if materials used in a concrete floor would react the same/hold up within an earthen floor. Your vote of confidence helps. We'll be putting this in over the course of the next month. I'll try to remember to update here!