Relearning How to Look at Piezometric Data for Seepage Evaluation: On-Demand

This webinar will start with the most basic seepage concepts and finalize on actual evaluation of piezometric data for earth dams and levees. Simple basic seepage ideas using high graphic illustrations will be the means to teach all concepts in this webinar. Also, numerous difficult concepts will be fully explained using high graphic simple illustrations. For example, this course will also provide unique insight into how seepage changes with simple geologic layer variations. A procedure for evaluating time based piezometric data versus reservoir data will be presented and it represents the only comprehensive method — the conventional procedure is to plot the data and then just look at it. This course also provides concepts for observing the potential for backward erosion using actual piezometric data. New procedures and standards for data presentation of field based piezometric data versus reservoir level will also be shown.

Key Takeaways:

  •     Participants will gain a deep understanding of the most basic seepage concepts that are not taught at universities or short workshops.
  •     This is the only procedure for evaluation of field measured piezometric data versus reservoir level trends.
  •     The backward erosion process can potentially be observed using time based piezometric data assessment.    
  •     Participants will learn best practice methods for graphical presentation of piezometric data.

Richard S. Olsen, Ph.D. P.E.

Geotechnical Consultant

TrustDirt.com

Dr. Olsen is an expert in evaluating CPT data, seepage failure for dams (and levees), and rapid field assessment of large landslides.

He has been a private geotechnical consultant for four years since his retirement from the U.S. Army Corps of Engineers (USACE) Headquarters (HQ). At the beginning of his career, he worked at FUGRO, HLA, and Dames & Moore. He was also a senior research geotechnical engineer at USACE ERDC Geotechnical and Structures Laboratory for thirty years. While at USACE HQ, he was the National Senior Policy Advisor and a technical lead for geotechnical engineering. 

  • Introduction
    • Seepage basic concepts
    • Seepage erosion concepts
    • Historical seepage erosion failures
    • Backward erosion research Seepage basics
    • Seepage through soil
    • Piezometers
    • Seepage head loss
    • Basic concepts of flow nets
    • Flow under and through earth dams
    • Pore pressure head loss through foundations Equivalent sand tube concept
    • Evaluation of geologically complex foundations
    • Simplification to an equivalent sand tube
    • Reservoir to tailrace flow concepts
    • Late plug effects
    • Leakage effects
    • Pinching effects
    • Comparison of flow for sands versus gravel Making a Reservoir Level versus Piezometer plot (RP chart)
      • The RP plot is just a structured way of plotting typical piezometric data
      • Setup of the RP chart for a uniform equivalent sand tube
      • Plotting reservoir levels on the RP chart
      • Drawing the RP line (U) to the assumed no flow point (N)
    • Plotting relationship for
      • different piezometer locations
      • early pinching of sand tube
      • late pinching of sand tube
      • leaking cutoff wall at different locations Backward erosion using the RP chart
    • Basic physical representation in a cross section
    • RP plotting for initial erosion
    • RP plot for continued backward erosion
    • Slope of line changes with continued backward erosion
    • Comparison of RP line slope decrease versus piezometer drop Comparing RP charts for real field measured data (about 8 examples) How to properly plot RP charts using field data How to properly make depth plots of support data such as permeability data Future needs Conclusions and summary

Key:

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On-Demand Webinar
Open to view video.
Open to view video. This is an ON-DEMAND version of the May 14, 2019 live webinar.
Post Survey
5 Questions
5 Questions Post Survey
Completion Quiz
10 Questions  |  3 attempts  |  6/10 points to pass
10 Questions  |  3 attempts  |  6/10 points to pass
Completion Certificate
2.00 PDH credits  |  Certificate available
2.00 PDH credits  |  Certificate available