Nebraska LTAP


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Song, C.R., Bekele, B.M. and Sawyer, B. (2018). "Piezocone Penetration Testing Device". Nebraska Department of Transportation Research Reports No. M063.


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.