1) DAMAGE DONE BY STONES (Yerushalmi Halachah 1 Daf 3b)

הכא את מר מפני שהסלעים מרתיחין וכא את מר אין מרתיחין

(a) Question: Our Mishnah said that he must distance stones from the walls of a pit as they produce heat and can cause damage; whereas the Mishnah in Maseches Shabbos does not say that they produce heat (or they would have been listed amongst the things that may not be used to insulate food even before Shabbos)?

אמר רבי יוסי כאן וכאן אין הסלעים מרתיחין אלא מפני שעושין עפר תחוח ומלקין את ארצות הכותל.

(b) R. Yosi: In both cases, the stones do not produce heat, but the reason they must be distanced from the pit is because they cause the ground to crumble around the pit.