Evaluation of Dynamic Cone Penetration Quality for Cohesive Soil Embankment Construction

Abstract

A pilot project at US-34 in Iowa recently required the use of a new quality control (QC) and quality assurance (QA) specification involving dynamic cone penetration (DCP) testing in concert with conventional moisture and density testing. The contractor's QC test results were verified with occasional QA testing by Iowa State University and the Iowa Department of Transportation. Cone penetration testing and laboratory unconfined compressive strength testing were conducted on samples obtained on natural fill material before excavation and afterwards on the compacted fill to evaluate the performance properties of the final product. The research findings documented in this paper focus on (a) statistical comparisons between contractor QC and independent QA test data, (b) statistical analysis of the contractor QC data, and (c) evaluation of the performance of a completed embankment. The study findings show that the DCP can be used for QC and QA testing for cohesive soils to evaluate stability and vertical uniformity.