Pitfalls in Quality Control Processes for Compacted Earth Fill
Recorded on November 16, 2010 (120 minutes)

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Quality control activities are important during the construction of an earth dam.  The quality control program is intended to ensure that the compacted fill meets or exceeds all the specifications for the earth fill in the construction contract.  The two primary specifications involve the degree of compaction and the acceptable range of water content for each zone in the compacted fill. 

This Webinar provides guidance on common pitfalls in the quality control process. 
The most common pitfalls that are covered in the Webinar are:

1. Failure to obtain and employ a correction factor that considers the difference between the water content measured with the nuclear density gage and the correct oven dry water content.
2. Failure to correctly determine a reference density test to which the field density test can be compared to obtain the correct degree of compaction for a test.
3. Failure to consider correctly the presence of oversize rock or gravel particles at a test site.  Failures include:
    a. not measuring the percentage of the oversize particles at all, 
    b. using a reference density test that was performed with a different amount of oversize particles than the test site, and
    c. not correctly measuring the properties of the oversize particles, the apparent specific gravity and percent absorption. 
4. Failure to determine the degree of saturation for each measurement made on the compacted fill during a QC project.  Failure to recognize the usefulness of this tool in evaluating the other pitfalls in QC measurements of dry density and water content that may occur earth dam construction.

The common pitfalls are related to the ASTM specifications where applicable.  While designed for quality control involved in the construction of earth dams, the same principles apply equally to the construction of any earth fill where construction specifications include degree of compaction and water content requirements.

Professional Development Hours (PDHs): Each paid registrant (whether viewing the live or archived version) will receive a link to the access the webinar and the post-event assessment tool.  Upon successful completion of the assessment, you will be able to print a certificate of attendance for 2 professional development hours.

Please note that registration for this session closes at 11:00 am ET on Tuesday, November 16, 2010


Danny K. McCook, P.E. is an independent consulting engineer specializing in the geotechnical analysis and design of small earthen embankments. In his 41 year career with the Natural Resources Conservation Service (he retired from there in October 2008), he prepared geotechnical design reports for hundreds of embankment projects across the US, He is the author of a variety of NRCS publications and training manuals on geotechnical topics. He has presented papers at 16 previous ASDSO National and regional meetings. He presented two webinars for ASDSO on review of embankment projects and common problem soils and conditions. He received a BS degree from Texas Tech University in 1965 and a MS degree from the University of Nebraska in 1967. He is a registered PE in Texas and a member of ASCE and ASDSO.

  1. Overview of QC process steps in an earth fill project
    1. Measurement of Moist Density and Water Content
    2. Computing Dry Density
    3. Determining correct reference test (reference Proctor)
    4. Computing degree of compaction and water content conformance to specifications
  2. Pitfall 1 Failure to determine correction between nuclear gauge and oven dry water content.
    1. How correction should be obtained at a project ASTM D6938
    2. Effect of failure to correct
    3. Example on evaluating effect of failure to correct water content for nuclear gauge
    4. Degree of Saturation Tool
  3. Pitfall 2 Failure to Correctly Consider Oversize Particles at a Test Site
    1. ASTM D6398 Nuclear Test precautions
    2. ASTM Practice 4718 for oversize corrections
    3. Example of failure to correct for oversize particles
    4. Rock correction equations and use of spreadsheet
    5. Examples and Problems
  4. Pitfall 3 Using Incorrect Reference Proctor Test
    1. Methods for selecting reference test for site at which measurement was taken
      1. Judgment or jar method
      2. Family of Curves
      3. Rapid 3 Point
      4. Full Proctor Test
    2. Advantages and Disadvantages
    3. Example showing Family of Curves Method
    4. Available Family of Curves
    5. Developing family of curves on site
  5. Summary