backfill material as soil foundation

[StewardMM]

We will be constructing structures on top of a backfilled material of 2.5m. depth of foundation is only 1.5 m. is it ok that a foundation will just be laid on a backfill material and not on the original soil?(please see attached drawing)

I fear that settlement might occur.

please advise.

thanks

 

[hokie66]

Your answer depends on a lot of variables, and you should be asking these questions of your geotechnical consultant.

 

[ztengguy]

What Hokie66 said. Ask what the backfill is? how long its been there? How was it placed?

 

[Ron]

I agree with the others...get a LOCAL geotechnical consultant involved. In general, structures are placed on select and properly prepared fill every day...it is common in my area. However, as noted by hokie66, there are numerous variables and the settlement of the fill is only one of those variables. I would probably be more concerned about overall settlement of the site area below the fill than the fill itself. The weight of the fill can cause significant settlement below the fill, depending on the subsurface soil conditions....that's why you need a local geotech involved.