deep excavation level need to be filled before doing the footing 1

[mshemy]

is it possible to backfill & compact a depth of 6-8m and then build the footing?

i have a problem in my project, the new received site, the site level have some area levels is lower than the excavation level by 6 to 8m.

is there any methodology supported by international codes ref. such ASTM describe this case.

Please support.

 

[Ron]

Yes, it's possible. It is called controlled, engineering fill. Must be done properly. It is also expensive to do so. There are no shortcuts. Do it right.

Is it practicable? Only the economics of your project can decide that.

 

[mshemy]

thanks for your reply, however the engineer will not agree unless i submit a methodology supported by international codes references.

can you support in such Ref.

 

[jayrod12]

No, you'd need a geotechnical engineer that is experienced with the project area as well as engineered fill.

There's no one code reference that will approve or deny the use of 6-8m of controlled fill.

That's a lot of fill though, are you sure that the current site level is 6-8m low? and if so, why does it need to come back up?

I'm envisioning major slope stability issues if your existing site elevations vary by that much.

 

[mshemy]

Yes, it is really vary that much as the site is huge.

the Engineer needs from us to:
Unauthorized Excavation: Consists of removal of materials beyond indicated subgrade elevations or dimensions without specific direction of the Engineer. Unauthorized excavation shall be at the Contractor’s expense.
1. Under footings, foundation bases, or retaining walls, fill unauthorized excavation by extending the indicated bottom elevation of the footing or base to the excavation bottom, without altering required top elevation.

actually we did not did unauthorized excavation, but this mistake happen when they firstly receive the site.

 

[jayrod12]

If the site currently exists with a 6-8m differential it seems odd that they wouldn't design the building to accomodate it. Hell, that's one large basement you could add.

 

[Ron]

jayrod...I agree! Geez...why not work with what you have. Ideal situation for entry at higher level, basement or other on lower level. Otherwised properly engineered fill.

 

[jayrod12]

Think of all the money you would save by just building basement walls. That engineered fill is going to be pretty expensive. I would bet the cost of a concrete basement would be pretty close to the cost of the fill. It's like a free basement.

 

[oldestguy]

I was thinking that, in answer to the first question of compacting uncontrolled fill, if the equipment is in the country, that these systems might be used. Vibroflotation has been used on naturally loose deposits. Also deep compaction has been used on fills with dropping of large weights, dynamic compaction. To evaluate the results, conventional test borings or test pits would verify the adequacy of the work. Of course piles driven through the fill also is an option.

I've used rolling surcharge on dumped fills, sometimes combined with replacing the upper 5 feet or so with compacted fill under footing locations.

 

[EireChch]

6-8m if filling sounds crazy! What is the site? Is it a subdivision with a lot of high spec houses proposed? Seems uneconomical, I would love to see a cross section throught the deepest fill height! Stability will be an issue, a lot of drainage may also be required!