×
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

Anyone made their own oedometer

Anyone made their own oedometer

Anyone made their own oedometer

(OP)
I hear it used to be fairly common for geotechs to have a machine shop make their consolidation/swell machines.  

I have a machine shop next door and thought I might try it.  Has anybody done this and/or have pictures they can share??

The basic concept seems easy enough, but I'm not sure of some of the specifics.  The ones I'm used to have a moment arm that starts at the sample and extends out to the weight.  I would think it would have to be hinged behind the sample, and at some point along the arm would press down on the sample cell.  I'm not sure how to calc the moment arm with a weight-to-hinge distance and a weight-to-sample cell distance.  

 

RE: Anyone made their own oedometer

Yup, I've done just that.

Yes some sort of hinge at the sample is needed, but not fancy.

A ball bearing resting in a depression also works.

You may need some counter weight, to balance out the weight of the long arm at low loadings.

RE: Anyone made their own oedometer

I wonder if anyone has ever experimented with a miniature oedometer, i.e. an oedometer that can accept a metal "sleeve" of clay from a split barrel sampler.  The sleeve would be cut with a band saw, say, 3/8" inch thick.  Based on some quick calcs, it looks like you'd only need about a 12 inch arm with reasonable weights to produce similar pressures as a conventional machine.  Besides the specimen probably being rather disturbed, it would be interesting to see how the results of that sort of test would compare with a conventional machince of standard specimen size.

RE: Anyone made their own oedometer

(OP)
Thanks Oldest, I like the ball bearing idea.  

After drawing the force diagram, I see that all I need to do is sum up the moments around the pin connector to determine the proper lengths for a 10:1 ratio.

One more question, did your dial gauge rest on the top of the sample (the metal piece the ball bearing would contact), or on top of the arm?


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