Pitfalls in Quality Control Processes for Compacted Earth Fill: On-Demand
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
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.
Danny K. McCook, P.E.
Consultant, McCook Geotechnical Engineering, PLLC
Danny K. McCook, P.E., who passed away in 2013, was 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 was the author of a variety of NRCS publications and training manuals on geotechnical topics. He presented papers at 16 ASDSO National and regional meetings. He received a BS degree from Texas Tech University in 1965 and a MS degree from the University of Nebraska in 1967, and was a registered PE in Texas and a member of ASCE and ASDSO.