Nebraska LTAP
Date of this Version
2-2-2018
Document Type
Article
Citation
Song, C.R., Bekele, B.M. and Sawyer, B. (2018). "Piezocone Penetration Testing Device". Nebraska Department of Transportation Research Reports No. M063.
Abstract
Hydraulic characteristics of soils can be estimated from piezocone penetration test (called PCPT
hereinafter) by performing dissipation test or on-the-fly using advanced analytical techniques. This
research report presents a method for fast estimation of hydraulic conductivity of overconsolidated soils
based on the piezocone penetration test. The method relies on an existing relationship developed for the
determination of hydraulic conductivity of normally consolidated soils on-the-fly. The present research
revises this relationship so that it can be applied for overconsolidated soils by incorporating a proper
correction equation. The revised relationship provides a pore pressure representing the hydraulic
conductivity of a hypothetical “equivalent normally consolidated soil”. The revised relationship was
developed with piezocone indices (Qt, Fr, and Bq) based on well documented laboratory test and PCPT
data. In this regard, PCPT data from Nebraska Department of Transportation (NDOT) was used as a
primary data base to determine the correction equation. Then, the proposed revised relationship was
verified for other sites in the USA, Canada, and South Korea. This study showed that the proposed
method provides a reasonably good prediction of hydraulic conductivity of overconsolidated soils. In
addition, the method also accurately predicted the hydraulic conductivity of normally consolidated soils.