×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Is compaction more than 100% in soil acceptable or not?

Is compaction more than 100% in soil acceptable or not?

Is compaction more than 100% in soil acceptable or not?

(OP)
I am working now for an project of oil & gas industry. Here we are doing river sand fillig activity in layers of 200 mm. The sand was already tested in laboratory and the result is MDD=1.75gm/cc & OMC=9.70%. On working site in situ we are doing compaction of river sand layer by 10MT Vibro roller and carrying out compaction test by core cutter method. On site Moisture content is average=7% or 8%. But sometimes resulting compaction is achieved more than 100% i.e. 101%,103%. Is that acceptable or not?

RE: Is compaction more than 100% in soil acceptable or not?

Think about what you're using the sand for and how the added density might be a bad thing. Heavy compaction of the layer will decrease the permeability of the sand but will increase the layer strength and stiffness.

In most instances, your compaction in excess of 100% would be acceptable.

All the best,
Mike

RE: Is compaction more than 100% in soil acceptable or not?

As long as the compaction percentage stays below about 105%, it is fine. When it goes up to the 105% range, it indicates you're likely working in a material that is different than your Proctor material. Run field check points if you suspect you are off the Proctor curve for that material.

RE: Is compaction more than 100% in soil acceptable or not?

yes, it's acceptable.

Then again, it's up to you to use the correct Proctor value!

f-d

ípapß gordo ainÆt no madre flaca!

RE: Is compaction more than 100% in soil acceptable or not?

First off, anyone who tells you that the OMC is 9.70 % is blowing smoke . . . 2 decimal places? Get real.

Yes, you can get compaction greater than 100%. Look at curves (textbooks) showing the compaction curve for Standard Proctor vs Modified Proctor vs Field Roller Compaction. Ron is right in that order of 105% or so of the standard Proctor may be a maximum - and your compaction curve is likely pretty flat anyway.

Mad Mike hit the nail on the head about river sands - you really should be using relative density rather than compaction (another error in the standard compaction - is the loss of water by drainage once you get to higher moisture contents - you can see the water oozing out the bottom of the mould - giving non-homogeneous moisture contents throughout the sample.

RE: Is compaction more than 100% in soil acceptable or not?

Is the core cutter method the right method in sand? I typically use sand replacement test or Nuclear Gauge Testing.

RE: Is compaction more than 100% in soil acceptable or not?

Core cutter in sand - not my choice. Either of the two you suggested or a rubber balloon method.

RE: Is compaction more than 100% in soil acceptable or not?

suggest that if this is a large enough project, conduct a test fill and then approve a method spec. no need for extensive testing

RE: Is compaction more than 100% in soil acceptable or not?

Your statement "The sand was already tested in laboratory" shows you need some "education" as to control of a job by testing. Sure that one test might mean something for some of the job, but it is wishful thinking that one test can control a whole job. Along with the "precision" commented on, most jobs never need or fit a mold like this. Be prepared for on the job lab testing. Also, is there always a need for high percentage compaction? Not usually, especially if no testing is done on natural on-site material yet that also is used for support, etc.

RE: Is compaction more than 100% in soil acceptable or not?

I would ask, "100% of what" There are different tests for maximum density; none give an "absolute" answer, but are relative to the energy applied. You are not alone....MANY people thing 100% density is a absolute maximum number; it is not.

RE: Is compaction more than 100% in soil acceptable or not?

Proctors on dead sand are a pain but cheaper than min/max density needed for relative density. Depending on how clean the sand is min/max maybe required if you're required to follow the astm (D698/1557).

For field testing I'd go with sand cone or nuclear guage... gauge will be best on a larger site.

To tack on to Bigh and oldest, use common sense...

Think about the test method versus the magnitude of compaction. Sub 105% is normal but most jobs will have numerous soils that don't fit just one curve

RE: Is compaction more than 100% in soil acceptable or not?

>The sand was already tested in laboratory and the result is MDD=1.75gm/cc & OMC=9.70

Is this the Maximum Dry Density or is it the Standard Proctor Maximum Dry Density? If it's the Standard Proctor Maximum dry density and you're driving loaded 797 haul trucks over it (extreme example), the SPMDD might not be appropriate. In theory there's a family of curves for dry denstiy and moisture content for a given soil where with higher energy the curve drifts up and to the left (higher peak dry density and lower OMC).

It could be that the compactive effort being applied is substantially higher than the test used to get the MDD.

It could be a change of material and a new proctor is needed.

At any rate, I suspect if you've made a fuss about it the person recording the test results will in future never report any values over 100% and simply revise them downards because doing otherwise might result in some angry engineer breathing down his neck and making life difficult.

RE: Is compaction more than 100% in soil acceptable or not?

Quote ( )

On working site in situ we are doing compaction of river sand layer by 10MT Vibro roller and carrying out compaction test by core cutter method

core cutter method is not appropriate for sand, especially where it is on the dry side and is typically used for clay. suggest using nuke gage and a sand cone for every 10 gage tests

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Solutions Brief - Protecting and Rescuing On-Ground Personnel
Keeping our warfighters safe and delivering them a competitive advantage is a key goal of departments of defense around the world. It’s a goal shared by embedded computing manufacturers like Abaco: we never forget who we serve.This case study describes how a major international contractor integrated an Abaco single board computer at the heart of its CAS/CSAR solution. Download Now
Datasheet - Top Enhancements Creo 7.0
PTC's Creo 7.0 has breakthrough innovations in the areas of generative design, real-time simulation, multibody design, additive manufacturing, and more! With Creo 7.0, you will be able to design the most innovative products faster than ever before, keeping you on the cutting edge of product design and ahead of your competition. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close