A late friend of mine was in a (Canadian) tank battalion in the Korean War. He mentioned that for quite a bit of the war they had dug into a hillside so only the turret was exposed. The ground was shale so they set off shaped charges to shatter it and make it (relatively) easier to dig out. They sat on a hilltop just behind the ridge and faced off against the North Koreans and Chinese across the valley. However, in their case these were fully functional tanks.
(He had plenty of other interesting stories about the Korean War.)