×
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

Best Piezometer to be installed on a dam
5

Best Piezometer to be installed on a dam

Best Piezometer to be installed on a dam

(OP)
Does anyone has any idea of what would be the best recommended piezometer to be installed on a dam?

Among the Neumatic, electric and stand pipe each of them have their advantages and disadvantages.

I have read that the neumatic could be the best one to be used a long term.

Please advise.

RE: Best Piezometer to be installed on a dam

I prefer vibrating wire piezometers to pneumatic. Pneumatic can be very temperamental, especially if you get any air in the system.

Open stand pipe are fine in course grained materials. In fine grained materials, open stand pipes tend to response very slowly to changes in pressure due to the volume of water that has to flow. You also have to be careful with the length of sand pack/screen since the pipe can allow water to flow from one layer to another.

I would not use electrically resistance strain gauge piezometers in a dam under any conditions since they tend not to be stable over the long term.

Mike Lambert

RE: Best Piezometer to be installed on a dam

(OP)
Thanks GeoPavetraffic,

Adding to your comments: The stand pipe is also not effective when dealing with cold weather as water freezes in the pipe.

RE: Best Piezometer to be installed on a dam

Many of the US Army Corps of Engineers dams in the southeast contain open pipe type piezometers. Much of the instrumentation on their projects are actually open pipe type: uplift cells, pore pressure cells etc. That has a lot to do with when the dams were constructed though. They are slowly starting to replace the old open pipe pz’s with vibrating wire type.

Some issues with the open pipe type pz are issues with surface water getting into the instrument, slow response to pore pressure (as GeoPaveTraffic mentioned), manual readings are required and personnel taking readings can make mistakes (human error). Never had issues with the water freezing in the instrument. I think lightning can be an issue with vibrating wire pz and the data acquisition system. You also have to worry about debris destroying the wiring for the vibrating wire pz if it is located near a spillway (uplift cell scenario).

I personally like the vibrating wire pz.

RE: Best Piezometer to be installed on a dam

Open pipe type pz’s also have issues with biofouling. So you will have to keep them clean. Which can be a major pain in the butt.

RE: Best Piezometer to be installed on a dam

short screen lengths! As it less than 2 ft! Make the screen length too long and you'll record an average over the screen interval. If there are higher heads at the top of the screen and lesser heads at the bottom of the screen you'll also set up a pump within the well. Just limit your screen length!

f-d

ípapß gordo ainÆt no madre flaca!

RE: Best Piezometer to be installed on a dam

Suggest to take a look at this book:

Geotechnical Instrumentation for Monitoring Field Performance by John Dunnicliff.

Although I have not implemented instrumentation for most of my projects, this was the textbook for my geotech instrumentation graduate course. It is very good.

RE: Best Piezometer to be installed on a dam

If rapid response is needed or you want automatic recording and/or transmission, vibrating wire piezometers are a good choice. If not, I prefer open standpipes because they can be checked using falling head tests, serviced by surging and flushing, and may have a longer life. A vibrating wire transducer can be hung in the standpipe for automation or remote reading.

30 to 50 years ago, most open standpipes had galvanized steel risers, which have suffered a lot from corrosion. In particular, risers that begin in soil and then pass through a concrete structure tend to rust through just below the concrete. I have not seen much problem with PVC risers unless the embankment underwent substantial settlement.

Freezing should not occur below the frost line. If the water level is within the frost zone or above the ground surface, insulation is necessary. Some have used a layer of non-freezing immiscible fluid on top of the water, but I have not tried it.

I was a fan of pneumatic instruments some years ago, but I think the VWPs are a better choice nowadays unless you have an unusual situation.

All types are capable of failure or unreasonable results. Be skeptical.

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

White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why it’s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now
White Paper - Moving to a Driverless Future
This white paper describes what we see as the best practices to support a sustainable engineering process for autonomous vehicle design. It exposes how to use simulation and testing in common frameworks to enable design exploration, verification and validation for the development of autonomous cars at a system, software and full-vehicle level to drive a mature product development process for automated driving. Download Now
Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. 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