Oofta
Legend
The dome either sits on top with the edge not being perfectly flat to conform or it penetrates. I choose the former - it goes snug to solid ground. That means it can also be set at the side of a cliff or wall and makes it a little more flexible which can include blocking doors and whatnot.If the dome has a flat floor, what does it do to the ground underneath, which is presumably not perfectly flat? Does it slice off chunks? Leave gaps for protrusions to poke through? Or does the whole hut just rest unsteadily on top of uneven ground?
I think it's both simpler and more balanced to say there is no floor, and the spell magically warms or cools the air inside. If the dome can be dug under, that allows noncasting foes a way to assault it--difficult and slow, but doable.
So yes, the dome can also be dug under in my game. Or just call reinforcements because it's going to expire. All sorts of options other than gather around the edge of the dome waiting to be pincushioned to death. Unless of course the opponent can travel incorporeal or in the ethereal plane.