Drilled pier installation in backfilled site

[citywhite]

what would be the right/cost effective procedure to install drilled concrete piers in backfilled site? (Please see attached)
-backfill with slurry fill and proceed with current design of piers
-or, backfill with cement treated native w/8" lift compaction 95% and modify the tip of the piers to be exteded to the equal depth of the backfill.

 

[Ron]

The cost effectiveness of your fill considerations will be more local than this forum can address.

Fill the area using whatever means you desire (my personal preference would be engineered fill), then do the drilled piers/shafts.

 

[Zambo]

Engineered Fill - you can achieve compaction which will enable you to construct your bored piles in accordance with normal procedures. The disadvantage is cost if the material is not readily available, and you have to take the existing soil off site. As Ron states this is a local condition that we cannot assess on the forum.

Cement treated soil - this may also achieve your requirements, testing is required. The advantage is reduced cost for buying the material and bringing to site, then you have to look at the cost of the cement.

Slurry Fill - not sure what you're referring to.