MB3 182b: Dragging a Chair on Shabbos (337:1)

The melacha of plowing is to make the land ready for planting. Filling in a hole or smoothing out land is considered plowing, doing so inside the house is a Toldah of plowing. It applies even if it's not designated for plowing.

Digging a hole on Shabbos to use the hole itself is a דאורייתא.

Dragging a chair on a dirt floor is permissible assuming you weren't intending to create a ditch (דבר שאינו מתכוון) unless it will almost definitely happen (פסיק רישא)

Dragging a heavy item on a hard floor.