Evaluation of subgrade modulus using weighted depth profiles

Lacey, David, Look, Burt and Williams, David (2012) Evaluation of subgrade modulus using weighted depth profiles. International Journal of Geotechnical Engineering, 6 2: 215-222. doi:10.3328/IJGE.2012.06.02.215-222

Author Lacey, David
Look, Burt
Williams, David
Title Evaluation of subgrade modulus using weighted depth profiles
Journal name International Journal of Geotechnical Engineering
ISSN 1938-6362
Publication date 2012-04
Sub-type Article (original research)
DOI 10.3328/IJGE.2012.06.02.215-222
Open Access Status
Volume 6
Issue 2
Start page 215
End page 222
Total pages 8
Place of publication Fort Lauderdale, FL, United States
Publisher J Ross Publishing
Collection year 2013
Language eng
Formatted abstract
The modulus (E) of a road subgrade is one of the most commonly assumed  parameters, yet generalized values are often used for input into design. The Plate Load Test (PLT) can be used for near surface evaluation of stiffness parameters, but it is comparatively costly and time consuming. In this paper, the PLT is correlated with a series of adjacent Dynamic Cone Penetrometer (DCP) tests, and details of both the field testing and the numerical simulation used to account for the stress envelope effect of the PLT to obtain reliable correlations are presented. The advantage of deriving a DCP → E correlation is that it would enable a modulus parameter to be estimated directly from a quick field test, whilst also potentially extending the  estimated E value beyond the depth range of the PLT. Currently, using existing correlations, one must generally convert the Penetration Resistance (PR) of the DCP to a modulus value via two levels of conversion (PR → Californian Bearing Ratio (CBR) → E). This two stage process introduces additional scope for errors. One aim of this research was to reduce these errors by directly converting the PR to an E value. Another objective was to incorporate the DCP depth profile into the conversion  between PR and E values at depth. Thus, the relationship between a varying stress PLT envelope and the DCP profile needed to be established. A Finite Element Method (FEM) model was employed to identify appropriate depth weighting factors to account  for the PLT’s narrow stress envelope. This study shows that the DCP can reliably  predict E values obtained from PLTs, as well as providing E values at depth for design purposes.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2013 Collection
Version Filter Type
Citation counts: Scopus Citation Count Cited 0 times in Scopus Article
Google Scholar Search Google Scholar
Created: Thu, 04 Apr 2013, 13:23:18 EST by Julie Hunter on behalf of School of Civil Engineering