×
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!
  • Students Click Here

*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

Jobs

Soil properties

Soil properties

Soil properties

(OP)
Hi everyone

Could somebody please help me out in defining the following:
Submerged density
Drained and undrained stress
and where are they used?

RE: Soil properties

I believe undrained stress is just what it says.  Below and above the water table.  Submerged density is probably how heavy the soil and water are together, ususally per cubic foot.  So that would be something like:

[Weight of soil + Weight of water(density of water at a certain temperature/volume of voids)]/volume of soil and voids

That's all from Soil Mechanics and Engineering Practice, Terzaghi and Peck; an old book but I believe the basics are still good.  
 

RE: Soil properties

"Submerged density" might also refer to what's more often called "submerged unit weight" or "bouyant unit weight," which is the total weight of the material (including solids and pore water) minus the unit weight of water.  This is what a cubic foot would weigh if it and the scale were under water.  

"Drained" and "undrained stress" are also terms that don't quite fit conventional usage, and out of context, their meanings aren't obvious to me.  I'd guess they mean "effective stress" and "total stress."  Effective stress is the unifying concept of soil mechanics.  It governs shear strength, compressibility, elastic properties, etc.  You should probably find an undergrad soil-mechanics text.

Bon chance!
DRG

RE: Soil properties

In following to what dgillette was starting, two theories are commonly used to estimate the shear strength of a soil depending on the rate (how fast the load is applied) of shearing. These are the Tresca theory for short term loading of a soil (commonly referred to as the undrained strength or the total stress condition) and Mohr–Coulomb theory, combined with the principle of effective stress, for the long term loading of a soil, commonly referred to as the drained strength or the effective stress condition.

recalling that effective stress is total stress minus pore water pressure.

My disclaimer is that I'm not a geotechnical engineer so I stand to be corrected, I just dug out my text book when I read this post because the terms sounded familiar, but I couldn't remember either.

  

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!


Resources