<p><p><h2>Preferred QC/QA Procedures</h2>Excavation and replacement is a common and routine method used by public agencies such that each agency has established procedures for QC/QA of fill materials, placement, and compaction, which may be applied to the replacement material. Construction quality is achieved by meeting established requirements, as detailed in project plans and specifications, including applicable codes and standards. Quality Control (QC) and Quality Assurance (QA) are terms applied to the procedures, measurements, and observations used to ensure that construction satisfies the requirements in the project plans and specifications. QC and QA are often misunderstood and used interchangeably. Herein, Quality Control refers to procedures, measurements, and observations used by the contractor to monitor and control the construction quality such that all applicable requirements are satisfied. Quality Assurance refers to measurements and observations by the owner or the owner's engineer to provide assurance to the owner that the facility has been constructed in accordance with the plans and specifications.</p><p>The components of QC/QA monitoring programs for excavation and replacement are listed in Tables 1, 2, and 3. The entries in the tables are a list of typical items, not a list of all methods that could be used for QC/QA. Some QC procedures and measurement items may also serve as QA procedures and measurement items.<br><h3>TABLE 1. TYPICAL EXISTING QC/QA PROCEDURES AND MEASUREMENT ITEMS</h3><table class='tablepress' id='tablepress-1954'><thead><th><center>QC or QA</th><th><center>Material or Process</th><th><center>Items</th></thead><tbody><tr><td ><center>QC</td><td ><center>Material Related</td><td >• Replacement soil type
• Replacement soil strength or modulus
• Replacement soil compaction characteristics
</td></tr><tr><td ><center>QC</td><td ><center>Process Control</td><td >• Delineate area and depth to be excavated
• Monitor groundwater location
• Evaluate soils exposed after excavation for stability
• Monitor thickness of soil lifts
• Monitor compaction of replacement material
• Monitor soil volume excavated
</td></tr><tr><td ><center>QA</td><td ><center>Material Related</td><td >• Replacement soil type
• Replacement soil strength or modulus
• Replacement soil compaction characteristics
</td></tr><tr><td ><center>QA</td><td ><center>Process Control</td><td >• Monitor area and depth to be excavated
• Proof rolling
• Monitor groundwater location
• Evaluate soils exposed after excavation for stability
• Monitor thickness of soil lifts
•Monitor compaction of replacement material
•Monitor soil volume excavated
</td></tr></tbody></table><br><h3>TABLE 2. PERFORMANCE CRITERIA USE IN QC/QA MONITORING PROGRAMS</h3><table class='tablepress' id='tablepress-1955'><thead><th><center>Topics</th><th><center>Items</th></thead><tbody><tr><td ><center>Material Parameters</td><td >• Strength/stiffness of compacted replacement materials
</td></tr><tr><td ><center>System Behavior</td><td >• Reduction in settlement or deformation for embankments or structures
• Increased support for pavements
</td></tr></tbody></table><br><h3>TABLE 3. EMERGING QC/QA PROCEDURES AND MEASUREMENT ITEMS</h3><table class='tablepress' id='tablepress-1956'><thead><th><center>Topics</th><th><center>Items</th></thead><tbody><tr><td ><center>Material Related</td><td >• None noted</td></tr><tr><td ><center>Process Control</td><td >• Intelligent compaction</td></tr></tbody></table></p></p>
<p><p><h2>QC/QA Guidelines</h2>Inspections, construction observations, daily logs, and record keeping are essential QC/QA activities for all technologies. These activities help to ensure and/or verify that:<br><ul> <li>Good construction practices and the project specifications are followed.</li> <li>Problems can be anticipated before they occur, in some cases.</li> <li>Problems that do arise are caught early, and their cause can oftentimes be identified.</li> <li>All parties are in good communication.</li> <li>The project is on schedule.</li></ul>Additional technology-specific details for inspections, construction observations, daily logs, and record keeping QC/QA activities are provided in the <em>Individual QC/QA Methods </em>sections.</p></p>
<p><p><h2>References</h2>Capachi, N. (1991). <em>Excavation and Grading Handbook</em>, Craftsman Book Company, Solana Beach, CA.</p><p>Christopher, B.R., Schwartz, C., and Boudreau, R. (2010). “Geotechnical Aspects of Pavements,” FHWA-NHI-10-092, Federal Highway Administration, Washington, DC, 568p.</p><p><a href="https://www.nhi.fhwa.dot.gov/training/nhistoresearchresults.aspx?get=&a…, E.J. (1994). <em>Construction of Fills</em>, Second Edition, John Wiley & Sons, Inc., New York, NY.</p><p>Trenter, N.A. (2001). <em>Earthworks: a guide</em>, Thomas Telford Limited, London.</p></p>