How much sand should I use to pack around a buried pole?

I'm burying some 18 in. PVC tubes in the ground. It's really important that they stay vertical, and don't shift at all when the ground freezes, so I'm packing sand around the pole. How much is enough to keep it in place?

As much as you can get. if you want it to settle and not move then add some water and tamp with shovel handle.

Think about this also: Putting something solid (concrete,rock, road base) is solid. If the ground moves, solid pushing solid will move whatever is in there. Sand being compacted and settled is softer. Solid pushing softer will allow softer to absorb some of the movement. Why do they put sand or pea gravel under concrete slabs, why is sand compacted around and under driveway pavers or brick?

Just a thought.

dry concrete mix is better than sand

the same amount you would use for a swede

none pack road base in it sand will move and keep moving

Maybe about 3lbs can do it. but u didnt explain much. depends how big the whole is to that ur putting that 18 " pvc in.

Its not so much what you pack around it but rather how deep you go. Here in Ct. I would have to set them below frost, 42" deep, and into 12" of concrete if you don't want any movement.
If all your doing is 18", nothing will stop it from moving.

Actually I wouldn't use sand.....its too soft and the pipe will shift around. Try using a gravel or sand-gravel mix...makes a more solid base.