Burying the Gate obviously doesn't stop the wormhole from forming. Having a Cover Stone doesn't either because the SGC's iris is basically one of those. So why has it been indicated that burying the Gate makes is so that when you dial in to that Gate, the chevrons won't work.
If you read my post in "Here`s a good one" you`ll see that the coverstone has two purposes and ways of being used.
Purpose A, as i`ve called it, is the function of the SGC Iris, to allow a wormhole to be activated but stop anyne from coming through.
Purpose B, is to be actually inside the ring and stop the wormhole from engaging in the first place. Although I`m not sure if a coverstone of this nature has ever been used.
Purpose A is most popular, being used by the Abydonians and hinted at by several others including The Nox(although they removed this to rescue the Tollan from the hands of the NID.) and the people from The Gamekeeper and numerous others.
That`s my senseless rant done with...