ISSN: 0149-6115
Page Count: 6

A Potential Model for Compaction Evaluation of Piedmont Soils Using Dynamic Cone Penetrometer (DCP)

Gabr, MA
Professor,North Carolina State University,NC,

Coonse, J
Project engineer,NCSU, Subsurface Inc.,

Lambe, PC
Adjunct associate professor,North Carolina State University,NC,

(Received 11 November 1999; accepted 27 November 2000)

Abstract

The potential use of the Dynamic Cone Penetrometer (DCP) as a compaction quality control tool is investigated in this study. The DCP is a simple device and relatively inexpensive to operate. Results from a laboratory testing program performed on three piedmont residual soils with appreciable fine content (> 60%) yielded correlation patterns for the estimation of moisture content (w) and dry unit weight (γ^dry), based on the DCP penetration rate (PR). The PR-liquidity index (LI) data were best correlated with an equation in the form of LI = A Log PR-Bm. For the test soils, A was equal to 0.65 and Bm = 1.2. On the other hand, the PR-degree of saturation (S) data were best correlated with the equation in the form of S = 1 − eCm*PR with the Cm coefficient estimated equal to −0.065. Using the principles of soil mechanics, w and γ^dry are calculated based on the predicted LI and S values, respectively. Using the water content and unit weight models, and on the average, the water content was underpredicted by 0.2% and the dry unit weight was overpredicted by 0.3 kN/m³. The developed model parameters are expected to vary for different soil types as well as compaction effort and a field calibration procedure in which moisture contents and dry densities are evaluated by alternative means, on a limited scale, is recommended.

Keywords:
California bearing ratio, compaction, dynamic cone, quality control, residual soil, saturation, subgrade, unsaturated

Paper ID: GTJ11349J
DOI: 10.1520/GTJ11349J
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