Filling basement - compacting gravel without drainage? Yes / No?

Our cellar is scheduled to be backfilled the week after next.
I have already received all the various answers about what would be best.

Starting point: The soil in which it was built is very clayey and is located on a slope, so water also comes from above.

The construction manager says we should compact with gravel without drainage.
The earthworks contractor says soil material from the neighboring property, which he would freshly excavate, with drainage would be best.

What would you recommend, or how have you done it before?

66 views, 0 answers. I speculate that the question is perceived as difficult to understand. If I squint and look deep into the crystal ball, I further suspect: You don't want to fill a basement, but the excavation pit around the basement. As far as earth or gravel are concerned, I would ask a third party (a geologist) where the two disagree. Without drainage sounds odd to me if the basement is getting waterlogged.

With us, the soil was also clayey and the working space of our basement was filled with gravel in which a drainage lies.

Did you have a soil profile created? You usually get recommendations from the geologist anyway. Without any further information, I would generally say: for clayey soil (which holds water well or even causes it to stagnate), always use drainage, otherwise the water will stand by the house, which surely isn't good for it.