The pseudo-N-value: proposal and applications

Koya Suto; Jun Sugawara; Victor Mocanu

doi:10.63929/08123985.2025.56.08

ISSN: 0812-3985
E-ISSN: 1834-7533

oa The pseudo-N-value: proposal and applications
Authors Koya Suto^1,2, Jun Sugawara^3,4 and Victor Mocanu¹
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¹ University of Bucharest, , Bulevardul Regina Elisabeta Nr. 4-12, București 030018, Romania ² Terra Australis Geophysica Pty Ltd, , 52 Nestor Avenue, Bardon, Queensland 4065, Australia ³ University of Wollongong, , Northfields Avenue, Wollongong, NSW 2522 Australia ⁴ University of Southern Queensland, , 487–535 West Street, Toowoomba, QLD 4350, Australia
Publisher: Australian Society of Exploration Geophysicists
Source: Exploration Geophysics, Volume 56, Issue 6, Nov 2025, p. 37 - 43
DOI: https://doi.org/10.63929/08123985.2025.56.08
- Published online: 01 Nov 2025

Abstract

The result of the standard penetration test (SPT) is expressed as an N-value and is commonly used for site characterisation in geotechnical engineering. Another indicator of integrity of the ground is the S-wave velocity, typically estimated by borehole measurement or seismic survey.

Many researchers have attempted to find precise relationships between these parameters. However, N-values estimated from S-wave velocity (Vs) using any formulae are subject to substantial errors, and the errors are inevitable due to the different nature of the parameters.

Pseudo-N value (Ñ) was first proposed in 2011 as Ñ= (Vs/60)^2.5. This is a simplified formula derived from those by previous authors. Using this simple formula as a common practice, with understanding of existence of error, the results can be compared from site to site.

This paper first compares the N-value and S-wave velocity in their natures, methods, practice and cost. Then it examines the previously published correlation formulae and proposed formula of pseudo-N value. Some examples of use of the pseudo-N values are presented.

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References

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/content/journals/10.63929/08123985.2025.56.08

The pseudo-N-value: proposal and applications

Exploration Geophysics 56, 37 (2025); https://doi.org/10.63929/08123985.2025.56.08

/content/journals/10.63929/08123985.2025.56.08

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Article Type: Research Article

Keyword(s): engineering; near surface; surface wave

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oa The pseudo-N-value: proposal and applications

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