Tee pee rings

[Malamute]

Used to be fairly common. Some have been archaeologically excavated - usually not much in the way of artifacts because often short term use by nomadic people. Hearths inside some.
As Phil Coffin said, rocks held down edges, even when there were stakes, and some, espec prehistoric ones, seem to have used rocks in preference to stakes.
Scholarly article with lots of historic tipi photos to consider the tipi ring question:
Banks, K.M. and J.S. Snortland 1995 Every Picture Tells a Story: Historic Images, Tipi Camps, and Archaeology. Plains Anthropologist 40(152):125-144.

The rocks instead of stakes has baffled me to a degree. Tipis function best with some air flow between the cover and liner. Mostly when staked down theres a bit of gap between the ground and cover that allows the air to pass between them and help draft the smoke out. Ive wondered if there was a trick they used to help that if the cover was set low enough to be held down with rocks.

This was my house for a couple years off and on in the 80s. I believe in this instance I just dug one channel through the snow in the back to give some air. I suppose a small area raised above the ground on the upwind side would do similar.