Engineered Fill Question?
Engineered Fill Question?
(OP)
What is the difference between "Engineered Fill" and for lack of a better term regular "Dirt"?
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Engineered Fill Question?
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RE: Engineered Fill Question?
Compaction can be obtained more efficiently and evenly because of the gradation.
While testing can determine the properties of your "dirt" there is always a need for stable fill, which will act the way you need it to act.
RE: Engineered Fill Question?
RE: Engineered Fill Question?
You can use any type of material from granular material to silts and clays for engineered fill provided you have the willingness to place it properly. Quite often the use of on-site existing fills or "dirt" is not suitable due to the variability of the material, debris, organics, garbage etc.
Types of material testing and test frequency depend a great deal on the type of material and source of the material being used as engineered fill.
Placement of the engineered fill materials is typically controlled and involves certain thickness of the material placed and proper compaction of the material.
Contrary to popular belief engineered fill is not necessarily a cure all for all sites. You may get too much settlement of soft subgrade soils. You will always have some settlement of the engineered fill.
Confer with a geotechnical engineer prior to proceeding. Too often the call is made after all the so called engineered fill is placed. When this is the case the so-called engineered fill can be considered dirt and may have to be restarted all over again.
RE: Engineered Fill Question?
How is the "Known Gradation" determined.........is it not through tests or seive analysis? And is an entire stockpile of engineered fill scrutinized/tested or are samples taken at a particular frequency?
These answers are typically spelled out in the project specifications.
It is not clear if you are reviewing someone else's design or developing your own design. If someone else's, then find the specs for the fill. If your own, then consult a geotech to help you write an appropriate spec for your site application of engineered fill. Also, many Dept of Transportations will have a standard spec for this sort of material, although it may not be called "engineered fill".
RE: Engineered Fill Question?
Non-engineered fill is not designed or specified by an engineer and the embankment does not usually get inspected or tested for quality control. Hard to tell what you will get with non-engineered fill or if it will be suitable for the desired use...
RE: Engineered Fill Question?
But to explain my situation, I am helping inspect the placement of fill at a site. The contractor was attempting to use the native soil but couldn't consistently achieve the required compaction percentage and was forced to remove what was placed. A different material was brought in from off-site but the contractor says it is non-engineered fill (or dirt).
I would just like to know:
How you determine the material is homogenous throughout the entire placement process?
How an off-site material is not considered engineered fill?
Does the type of compaction equipment and the number of passes matter if you achieve the require moisture content and density?
RE: Engineered Fill Question?
If a suitable soil type for structural fill passes the gradation analysis and any other soil requirements specified and is placed and compacted properly, should it not be "engineered fill"? I believe the posters here agree with my take on it.
Apparently, we're wrong.
Here is what I've deduced are the requirements for "engineered fill" according to people I've met in the field, and since i've had to communicate with them, I've adopted it as well (after i've seen the soil on-site, of course).
In piedmont and coastal North Carolina, "engineered fill" must
1. come in a truck from a quarry
2. at the quarry the material was graded by adding different materials of uniform gradation together and mixing. (perhaps this is the engineering of it? done by bulldozer engineers!)
The "engineered fill" i've seen has been a sand mixed with small crushed gravel.
The point of this post is that there may be an engineering language issue and it may have a regional aspect to it. Your "engineered fill" might not follow the rules i set or it could be like oranges and apples if you compared a bucket of ours verses a bucket of yours. I prefer to talk in terms of "structural fill" since most people agree on its meaning. The "engineered fill" i've seen has one engineering property that most SOILS don't (let's agree not to call it dirt either, such a dirty word) and that is that water infiltrates very fast if it has somewhere to drain to.
But the drainage aspect could very well be specific to our apples.
hope this doesn't confuse it,
dsg
RE: Engineered Fill Question?
You will have to test the borrow material to determine if it's properties are acceptable.
If it meets the specifications and QA/QC and is accepted by the Engineer, than it is "engineered" - regardless of what your contractor says...
Probably doesn't matter, but a good question for the geotechnical engineer
RE: Engineered Fill Question?
Engineered fill - if the fill moisture conditioning, placement, and compaction is observed and documented by a credible engineering firm, and an appropriate number of field density tests and laboratory tests (material specification compliance and compaction) are taken and the fill material and completed fill meet specification, then I'd suggest the fill is "engineered." With this information you can make an informed estimate of the material's engineering properties, and then estimate how the material will perform under design loads.
RE: Engineered Fill Question?
RE: Engineered Fill Question?
Variation in the fill affects its engineering properties.
Suitable testing is needed to document the as-placed condition.
In the absence of suitable testing the completed fill is unknown.
As a result, you may not be able to depend on its engineering properties.
Hope this helps.
f-d
¡papá gordo ain’t no madre flaca!
RE: Engineered Fill Question?
RE: Engineered Fill Question?
RE: Engineered Fill Question?
RE: Engineered Fill Question?
RE: Engineered Fill Question?
RE: Engineered Fill Question?
RE: Engineered Fill Question?
Natural or artificially graded mixture of natural or crushed gravel, crushed stone and or crushed sand with a least 90 percent of material passing 38 mm (1-1/2 in.) sieve and not more than 12 percent passing No. 200 (0.075mm) sieve
sometimes a maximum LL of about 40 and a PI not higher than 12 is specified.
So, if you see this material is quite specific and it is easy for someone with certain CMT or Geotechnical Trainning to identify this materials at the jobsite
In the other hand, it is not just the material characteristics, engineered fill involves placment controls, thickness should be surveyed, moisture content should be within a certain range, and a minimum percent of the maximum density should be reached.
by the way, engineered fill is not a magical solution and certain conditions should exist to use it to built something on it and geotechnical engineer based on some theories and experience determine if it is a suitable solution, who could imagine that colum stone could work simply drilling a hole in soft soils and filling the hole wit gravel, and it realy work.
RE: Engineered Fill Question?
RE: Engineered Fill Question?