×
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

percent strain on consolidation tests for 2 to 1 method

percent strain on consolidation tests for 2 to 1 method

percent strain on consolidation tests for 2 to 1 method

(OP)
i posted this question before and no one replied... am i not clear or does no one know what im talking about?

when calculating settlement with the 2 to 1 method the percent strain versus the pressure is needed... now do we need to take the "log" of the pressures similar to calculating the Cc and Cs(Cr)? or do we just care about the percent change over the related pressures?

thanks     

RE: percent strain on consolidation tests for 2 to 1 method

The 2:1 method gives you the "stress" increase at any level below the foundation.  Not really true since at any level the highest stress will be at the centre of the footing and lower stresses away from the centre - but overall average is about as per 2:1.  Knowing the stress increase at the various levels, you can, for finite thicknesses determine the settlement caused by the stress.  The simplest way is to use the elastic formula for strain = stress / E - or settlement = stress x thickness / E.  Use average value of E over the range of stress from existing to increased stress, use correction for 3-D as (1 - mu) approximately.  That is one way you can do it. There are several caveats in this method.

Another method is the Schmertmann method.  You don't need to compute the "stress" increase in this method. You can also use other elastic formulas where you have correction factors for rigidity of footing, corner and centre of footing, etc.  These are given in Bowles.  Other methods are also available.  

The above deals with "elastic sands" where the applied loading is nearly linear - not towards the failure load.  It also will be good for immediate clay settlements.  For clays you will need, though, your consolidation computations (with the stresses determined by your 2:1) method for determining the consolidation settlements.  See any good soils text on these issues. and then, there is creep settlement, etc.  Many pages of books and numerous papers dealing with this subject.

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